BR Dynamic Zoom Stuttering, edge artifacts

R 20 b3
OS 15.5 release
M1 ultra 128gb

working with project from R19, there are a number of still image clips with simple dynamic zoom moves. just simple "drifts" of small pos move, scale a bit. Depending on circumstances- if I reposition the clip, its been rendered / cached or not, scaled a bit, especially if clip length is adjusted, I have various problems :

Stutter between old settings and new settings : caching sometimes, other times this happens during live render playback, especially if the length of the clip has been adjusted.

Edge artifacts - generally black edges, especially if image has been cropped / softness used.

Fix1 : disable dynamic zoom on clip, then enable. it appears then DZ recalculates its move and things work as expected.

Fix2: mess with crop settings, or softness will usually clear the problem.

DZ needs to recalc itself better when clip changes would cause DZ to need to update itself or invalidate its cache.