Classes were not the same error when I diff PatrolGuard2 animation

When I click on PatrolGuard2 animation, open Source Control>History window, then RMB on the previous commit and “Diff against previous revision” menu, I get this error:

LogAssetTools: Warning: DiffAssets: Classes were not the same.

The diff tool worked for the other asset in the video. I’m on UE 4.26.2.

I think I can just continue the course, maybe someone knows how I can fix this, thanks.