I've removed it from 2.50.x:

1. It was not correctly incorporated, since it was added to 2.50.x without updating master. It is a complete disaster for the two branches to use the same quest rule bit for different purposes! (all quests saved in 2.50.x would work incorrectly in future ZC versions).

2. The same issue is already fixed in master using a different mechanism (ZASM version metadata, rather than quest rule). Master's mechanism needs to be removed and replaced with whatever 2.50.x does, if 2.50.x is changed to do something different.

3. From the threads here and on PureZC it doesn't sound like anyone will be affected by just rolling back the 2.50.3 COMBOSDM behavior.

If you need to put the quest rule back in for some reason, please ensure points #1 and #2 are fully addressed.