Tests fine in Origins (Fabric)
Version: 1.20.1-1.10.0.1

Thanks for this report. Ill fix it when i can.

It relates to the negative coordinates. At (100, 100) the detection is perfectly fine, but at (-100, -100) it is detecting (-99, -99).
I'm sorry, but is there an expected time for this to be fixed? My players are already abusing this bug :/

Expect a release in the first or second week of this month.

Okay, I've gone in and fixed the issue.

The issue was that the conversion of the exposed_to_sky condition check did not use the block position of the entity, but rather the regular position, with dropped decimals.

So standing on -99.5 would result in checking -99, rather than -100.

Will be fixed in Origins Forge 1.10.0.8