Custom low weight idle animations prevents return to higher weight?

I am trying to do a complete swap out of the default R15 animations with my own animations. The script I am using is just the standard Roblox animation handler in StarterPlayerScripts and just swapping out the animation IDs. The idle animation with priority-idle weight 9 runs fine, but when any of the priority-idle lower-weight animations trigger (usually the character looking around or swinging their arms), the results are the animation plays, but the character does not return to their default idle state.

Essentially after when the low priority idle animation plays, the character freezes up until any other action is performed. How do I prevent the freeze-up and get the smooth idle animation transitions?