TS is able to repro this in X3b. When it happens, I get the same results in 8.5. There is something that is gettig corrupted by X3 in a shared component. So basically, Groove clip looping is down for the count for me.

Real close as in the clip is still longer than 12 measures? By how much?

The original tempo is getting set to something than the set tempo. My project tempo is 120, but when I go to groove loop the clip, X3 changes the default tempo to 160bpm. Someone made a bad calculation somewhere in the code. Right now, Groove clip audio is broke for me. this has affected all versions of SONAR that I have.
 
Groove clip midi works as expected.

brundlefly
Real close as in the clip is still longer than 12 measures? By how much?

the clip is the correct measure wise, but the audio is pushed out a little and out of sync. I believe the cuase is found out. TS is opening a problem ticket on my behalf. They were seeing the exact same results as I was. Now their GCL does not work for audio...

Is no one else getting this? Isolated problem?

TS was able to get this recreated. You can too if you keep trying with X3. ;)   TS was using X3b.

I am able to reproduce a 12-bar clip stretching to 16 and showing 64 beats in clip properties, but changing it to 48 beats fixes it completely. I was not able to reproduce the other one where bars 3-6 were cut out of a 6-bar clip and groove-clipped. That gave me a 4-bar clip that looped as expected.

ive had this issue but only once in a while 8.5, x1, x2 and in x3 but as Dave said, changing preference's to round out the count makes it work fine.
I find sometimes there are clips that sonar doesn't quite get, so it needs a little assistance.
I work with grove clips on a daily basis. and have found every once in a while it needs a tweak.
it does well with reading minds, but every so often it needs a push.

Edit- sorry, I got here late, ignore ...  This is just Sonar mis-estimating the number of beats in a clip. Happens occasionally. To make sure it's being grooved properly, before you groove it, first make sure the clip begins and ends exactly at measure boundaries for the tempo you recorded it. Then ctrl-L to groove it. Then take a look at the clip's groove properties in the inspector. If the number of beats is wrong, change it in the properties. Then it should line up and extend just the way you expect.

So bvideo,your saying to ignore all of the instructions you just gave?