Seems like scene `RenderData` only gets synched once from `Scene` to
`BaseRender` in `RE_InitState` .
Animation on it is only evaluating on the scene, so the the `BaseRender`
`RenderData` is not properly updated here.
However `R_STAMP_DRAW` is part of that and it is the `BaseRender`
`RenderData` that is checked in `do_render_full_pipeline` (not the
`Scene` one) to determine if we want to stamp.
Later calls to `BKE_render_result_stamp_info` / `renderresult_stampinfo`
/ `stampdata` always get passed the scene, so individual animation stamp
details (such as Render Time) work properly.
So to resolve, use the `Scene` `RenderData` (rather than the
`BaseRender` one) for proper animation update.
NOTE: I noticed a comment about thread safety in `RE_InitState`, not
sure if this is relevant here
NOTE: this (not updating animation of members of `RenderData`) might
actually be a problem elsewhere, too -- havent checked on this in detail
though
Philipp Oeser