Hello,
I play on the ModPack Chroma Technology 2.
I'have trained all my bees with the attribute "Weather Tolerance: Any", but none of them leave the nest when it's raining.
The modpack currently use the last version of the mod: productivebees-1.16.5-0.6.9.18.jar.

I think it only helps them stay outside if they are already out when the weather changes. I'll add to my list to get it fixed.