When I rip a Bluray to MKV I do select the Subtitle track(s) in my favourite language and I also check the option "Forced only".
If the Subtitle track does not contain any forced subs, MakeMKV removes the unnecessary track at the end of ripping.
When I rip the disc without checking the Option "Forced only", the content is in the end equal, but the file size differs (about 100-500 Bytes). It's not really a problem, but I noticed that.
Another thing, which is really strange to me is that the file size differs also sometimes, if I rip a disc with the same settings twice. Shouldn't both files have the same size in that case?