I used to be able to select a part of an audio track and apply groove clip looping and it would maintain it's tempo. Now it either stretches or shrinks it and therefore makes it unusable. I'm pretty sure that it's a user error. Can someone point me in the right direction to get it to return to it's old behavior?

Hi. Do you "bounce to clip" before turning into a groove clip?
All the best.

I used to just split it where I wanted it to loop from, right click, and apply groove clip looping.

Is this a self recorded clip, or an imported one?

Usually imported
 

I think it's trying to change the tempo to match the template that I've imported it into.

Then I suppose there are some kind of time stamp to them, which needs to be removed before a new groove clip will be created correctly.
I could be wrong, though.

I messed with the settings somewhere awhile back experimenting with something and I think I messed something up.

I'll give it a try

if clip length changes SONAR guessed the number of beats wrong. Correct it in the Loop Construction View.