Thanks so much for looking into this. You can find the set of files that link the first and the second but not the third here: fif.zip. The only processing done was maxfilter. However, I noticed that the second (-1) file is much smaller than the other two, which is abnormal.
I say "correctly linked" to mean that sid and sid-1 become sid_tsss_mc (2) in the Brainstorm GUI. But for the set of files I have provided, I should get sid_tsss_mc (3).