No leaves turn white for me. I mentioned this earlier and the issue was erroneously closed as "not planned". I have waited in a snowy biome while it has been snowing for several minutes. See the screenshots below.

https://imgur.com/a/DVrHXSW
https://imgur.com/a/qyylkkb

Huh what resource pack or mod is adding that foliage to the leaves? It should theoretically be compatible, but I'll check right now.

Vanilla tweaks

I can confirm that without any resource packs (except "Fabric Mods" and "Default") it is still not working.

What version of the mod are you using? The latest version works fine for me. Also a list of yout other mods, if any, would be helpful

I believe I have the latest SnowyLeavesPlus version from CurseForge: snowyleavesplus-0.1.4

Mod list:

AmbientSounds_FABRIC_v5.2.14_mc1.19.3
BetterF3-5.1.0-Fabric-1.19.3
CameraOverhaul-1.4.0-fabric-universal
cloth-config-9.0.94-fabric
CreativeCore_FABRIC_v2.9.3_mc1.19.3
dynamiccrosshair-4.1+1.19.3
eating-animation-1.9.1
fabric-api-0.69.1+1.19.3
fallingleaves-1.14.3+1.19.3
InvMove-1.19-0.8.1-Fabric
iris-mc1.19.3-1.5.0
modmenu-5.0.2
PeacefulSurface-1.19.3-v1-fabric
physics-mod-2.9.4-mc-1.19.3-fabric
PresenceFootsteps-1.7.1
snowyleavesplus-0.1.4
sodium-fabric-mc1.19.3-0.4.7+build.21
soundphysics-fabric-1.19.3-1.1.0
Terralith_v2.3.6

Yep that is the latest version! I'm immediately sussing out falling leaves, I'll test that now

Hmm interesting it works fine with falling leaves (kind of unexpected tbh). I'll have to replicate your mod list and test it. I don't have time today, so it might take a bit to figure out the issue.

I went to a snowy_plains biome just now and it started working right away... I'm pretty sure I waited for several minutes in the other biomes where it looked like it wasn't working but I dunno... If I just didn't wait long enough I'm really embarrassed. AFKing in snowy_taiga again to check.

Yep, it worked in snow_taiga too. Kill me.