[Top Jimmy]

Every time you start a new midi note, you're starting the loop over again. If you've programmed a 1-bar loop, then you should have nothing less than a 1-bar note. Since you're in slip mode, is the end of the note hanging over just a touch? Switch to grid mode and make sure the note begins and ends in the right place.

*Edit* OK, I realized I'm wrong about the loop thing in Boom since it follows beat clock from the PT transport. But loops in other instruments like Xpand2 would start over at every midi note.