Why would SM add songs like BM in the new album as new audios?

What’s going on with SM bruh?

Probably so that the uploads all have the same cover on the Youtube Music app

Well those are only available digitally, so makes sense to add it on physical albums. Sometimes companies don't, sometimes companies do.

Check the physical album once you get a copy and if they're included in the tracklist and/or included as bonus tracks.