Hi. In case this can help another soul out there.
I came across this problem with a deformer. I’ve seen people in the forum with similar problems but I cannot tell if this is the same issue.
HARMONY 12.2
One drawing, one deformation created using “Create New Deformation Chain” button (In Mac, but the file behaves exactly the same in Win)
The transformation-switch, the one the program creates automatically, lose the target (“Drawing Path”) after a particular frame (389 in my case). At that point you cannot see the deformation chain anymore, and there is no deformation whatsoever. It doesn’t matter if you replace the whole chain, or the name of the chain. It is impervious.
If you copy the chain to other file it will behave the same way. I’m positive the problem is this node. Maybe it’s retaining a previous length of the film? (It is a test animation, and the length has changed). But I tried to reproduce it in another project and I couldn’t.
The fix is simple: create another transformation-switch straight forward for this drawing (if you don’t really need a transformation switch just deleting it will work). You can create one in node view and assign it to the element with the (by default hidden) assign transformation-to_element button.
I don’t know how to reproduce it, so even if this is a bug this won’t help much 
thanks,
J