(See my post below for updates on the weirdness.) Original post:
Hey all, suddenly my "comp" recording stopped working as it used to - I now hear previous takes while recording, which is the way sound-on-sound is supposed to work, but not comp recording. Splat used to automatically mute previous takes, but now it mutes all but the most recent take. In other words, say I have laid down 3 alternate guitar solos & want to do one more. When I go to record I can hear take 3 while recording take 4, but takes 1 & 2 are muted. If I loop the section it does the same thing, or if I stop, rewind, and hit "record" it does it. I'm sure I have fat fingered something somewhere, but cannot figure it out.
 
Anyone seen this before? Or does anyone know what dumbazz thing I may have done? Thanks!

right click on record button to open preferences & change

Thanks, Brandon, but maybe I wasn't clear. It is NOT set for sound-on-sound. It is set for comping, but acting like sound-on-sound. Checking the settings by right-clicking the record button was the very first thing I did. If there is another setting somewhere else, or some known bug (similar to the FX toggle fixing no metronome) I would appreciate any help anyone can offer.

You could try going into the actual preferences [under edit or file ] and change it there. Even if it already says comping change it to something else and then back again.

Yup, tried that, too. No joy.

Have you made sure Exclusive solo isn't on ?
 
Have you expanded the lanes to see if some have become unmuted ?

Thanks for the ideas, Chuck, but neither is the problem. This is only happening in this project (so far) and I've been using Sonar long enough to check all the obvious things. (Of course, I have missed obvious things in the past, so it's always good to have someone remind you to check them.)
 
I'm not using the solo function at all while recording this new guitar part, so the "exclusive solo" feature shouldn't matter. It's not on, at any rate. Sonar automatically mutes previous takes when you record in "comp" mode, but right now with this project it mutes all but the most recent take. It was not doing this when I began the project, so I am sure that I have inadvertently hit some key or combination of keys that has caused this.
 
Another symptom is when recording with the take lanes open the wave form that I normally see while recording does not appear until I hit stop. Again, it wasn't doing this 3 days ago on this project. Later today I hope to have time to dig into it a little more & try a few things. I'll let you all know if I find a solution, and if anyone has any other ideas, feel free to through them out there. I appreciate the thoughts from everyone so far.

could you possibly have a hidden track somewhere in your project?

bz2838
could you possibly have a hidden track somewhere in your project?

I wondered that, as well, and that was one of the many things I looked at while trying to trouble shoot this issue. Unfortunately,  that's not it, but thanks for the suggestion. :-)
 
I spent a bunch of time yesterday doing tests & experiments, & I'll post the results in just a bit. Gotta run a couple quick errands, then I'll have time to post the update.

Okay, so here's the updated weirdness that is happening, along with excruciating detail on the project. This project use a 16 track template, all audio tracks. I added a MIDI track for the drums, so we have a total of 17 tracks. I record scratch bass on one track & 2 rhythm guitar tracks, and the auto-muting function works just fine during recording. All of these takes were done as straight beginning-to-end takes, then I would go back & punch in to fix any mistakes or make changes, which is where the auto-mute was evident, using comp recording.
 
Then I add a melody guitar, using the looping feature so that I can try some variations on what I'm doing with the melody. So far, so good; auto muting during comp recording works fine. Once I'm happy with the arrangement I go in and record the drums to a click, and again, so far so good. Then I record permanent bass & rhythm guitar tracks. It's all still good. Then I go in to record the permanent melody guitar and the issue pops up: I can always hear the most recent take, which should be auto-muted when I hit the record button. After monkeying around with it a bit, I post the original question here at the forum. Several folks offer up suggestions, I double check everything they suggest, but no joy.
 
So yesterday, I really dig in and experiment, and this is where it gets even weirder. The melody guitar is on track 8, and I have four other tracks with guitars (in addition to the 2 rhythm guitars) that do only 12 measures of these little harmonized flourishes. I recorded some nonsense parts on each of those four tracks as a test, and the auto-mute worked just fine. I do the same experiment on the bass track & the two rhythm tracks; auto mute works fine! I go to some empty tracks & record some random stuff with both the loop function and just recording, stopping & recording again, and the auto mute works fine. Only on track 8, it still fails to mute the most recent take automatically. Ultimately, I test all 16 audio tracks, and auto mute during recording works on all but track 8. I have opened up every menu I can find, and all of the tracks appear to have identical settings. So... I quit, lol.
 
When this problem popped up I only had one little 4 measure section on the melody guitar that I kept flubbing, so I just let it go for a day, went back the next day, manually muted the take lanes, played the part right, and got on with the rest of the project.
 
I had hoped to figure out what caused it, so I could avoid the issue in the future, but I'm going to attribute it to the ghost in the machine, call it a one-time bug, and forget about it. Thank you to all who offered suggestions.
 
Oh, here's the other weirdness: at one point near the end of the song, which has a very funk feel to it, you can hear what sounds like someone doing a little "uh" type of grunt. It's rhythmic, and at the end of a cool little riff. Problem is, no one but me was present during any of these sessions, and I didn't do it. If I solo each track out, trying to find it, the "uh" is not there. But if I solo the two rhythm guitar tracks you can hear it. And it does not sound at all like a guitar sound (finger scrape, pick hitting a muted string, etc) but definitely sounds like a soulful dude going "uh." I'm leaving it in, 'cuz it fits & I'm too weirded out by it to try to fix it, whatever "it" is, lol.
 
Thanks again, everyone. I'm off to lay some guitars down for a couple other tunes. Hopefully the ghost in the machine will not play any tricks on me with those.