This is indeed really nice to know ! 
Hi semar,
The problem with the qualifiers seems to be that there is code inside of RunLoop.js that is called only if a frame has a transition applied to it (such as fade in). When that code runs, it calls a function named unBranchPrograms that clears out the list of qualifiers, which results in that null error when the program tries to access them after the fade in. I've come up with a way to fix this.
Fix 1:
This fix involves deleting line 668 in RunLoop.js that calls unBranchPrograms after a fade in, which will prevent the qualifier list from being cleared out.
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Fix 2:
This fix involves adding a line to RunLoop.js. Just add this.rhEvtProg.qualToOiList = this.rhEvtProg.qualToOiListFull; below line 668 as shown below:
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You can also undo the patch I suggested for line 1385 in my earlier messages as it is unnecessary and didn't target the root of the issue.
(2/5/25 Edit) The correct fix was actually to remove this.qualToOiList = null; on line 4365 in Events.js as per Yves' Please login to see this link.
Disclaimer:
I didn't write the runtime, nor am I familiar with all of its components, so I can't guarantee this is definitely the correct solution. I would at least try this fix though and see if you encounter any issues (whether they are related to qualifiers or not). If you do, please mention them here.