dea1c1b9eb
During scene copy modifier mask strips are relinked to point to strips in new scene. If strip used as mask is in different seqbase, this can fail, if seqbase is not copied yet. Add SEQ_DUPE_IS_RECURSIVE_CALL flag to avoid relinking modifiers during recursive call. Reviewed By: brecht Differential Revision: https://developer.blender.org/D7412