[Solved] Strange Problem - Input Echo Latency Problem on one song only

Are you also monitoring from your interface?
 
What are your reported latency values in Sonar?
 
What happens if you hit 'E' on your computer keyboard to bypass all effects, and then try it?  (Hit 'E' again after testing, to turn effects back on)
 
Bob Bone
 

It really depends on which effects are present.
 
Certain plugins, like Perfect Space and Boost 11, are simply not meant to be used for tracking/recording.  The nature of how they process adds a bunch of latency, and that will always be the case.  The 'fix' for that is to only add those kind of effects once all the recording is finished, and you have moved on to mixing.  Then, add in those kinds of latency-inducing plugins and jack your ASIO Buffer Size way up to accommodate the increased latency from the 'mixing plugins'.  Because the latency is at that point quite high, you will simply not be happy trying to record, which is why you only use them in the mixing process, where high latency doesn't matter.
 
So, bottom line - use low-latency plugins while recording, or no plugins (some folks do that), and keep latency low.  Then, add whatever plugins you wish for mixing, and adjust the ASIO Buffer Size accordingly.  You need to know the consequences of any plugins you plan to use, so you can avoid the situation where you have the plugins added already and then find out there is a problem.
 
Effects that use look-ahead processing or chew up CPU, are not likely to work well while recording, so do your research ahead of time, and you will be much happier.
 
I hope that makes sense.
 
Bob Bone