Crash happened in versioning code on NULL dereference in function seq_convert_transform_crop() for Strip crop and transform fields. Strips created after rB1fd7b380f4cf were assumed to have crop and transform always initialized, but this wasn't the case. This has been fixed in 2.90, but not in versioning code. Initialize these fields if they are not initialized already. Reviewed By: campbellbarton Differential Revision: https://developer.blender.org/D10463