Just that actually changing it at runtime won't do anything.
This deals with a nasty initialization order issue with encoding.
Encoding is initialized after options have initialized, but before
--load-scripts is checked and executed. Encoding initialization accesses
FFmpeg API, thus it has to run after FFmpeg is initialized (which also
implies it's initialized after options/logging init). On the other hand,
it sets the encoding builtin profile, which possibly sets --load-scripts
to "no". That failed at this point because --load-scripts was marked as
fixed.
Just marking it as not fixed gets rid of the headache, even if it's not
perfectly orthodox.