Since switching to the 64-bit versions of Cool VL Viewer on Mac, I've observed an odd behaviour from some flexible prims such as fluttering flags. Essentially it appears that when the prim flexes to a new position, its previous position "lingers" for a short period, producing a "double image" effect. I have linked pictures of a couple of examples. I don't know if this is Mac-specific, but it does not appear in Firestorm, or the SL viewer, so it does seem to be specific to Cool VL Viewer. The problem does
not appear in Cool VL Viewer 1.26.20.42, the last 32-bit version I ran.
Four-winged eagle:
Double-flag boat: