Thanks!
That measns, I am not the only one stumbling over this ;)
... I think, Kemper had a quite easier job here, as their "block positions" are fixed and Stadium is much more flexibel on the positioning of effects, cabs, amps... (and even more than one cab/amp). I can understand, that this flexibility makes it quite hard to program a "global cab-off"-button for a specific output... it would get hard, if someone uses more than one cab (for whatever reason) or dual amp setups with two cabs (for whatever reason...)
Maybe that is the reason? .. on the other hand, Line 6 seem to be very creative and may find a way to still do this ;)
Til than, I will try to not forget adding splits to my presets.. however, it feels not too good, because again its limiting flexibility: Cab needs to be the last block in the chain. I would have compressor, reverb, EQ afterwards, if there would be a way...