1.8.1 compatibility issue about full-slabs

[ModMan2021]

When loading up an old world (in my case i upgraded my 1.16.5 world) combined with the newest version of fixed water logging mod, it weirdly made a lot of blocks automatically waterlogged (created water blocks) Leaves, redstone torches, doors, this didn't happen if i only used the water logging mod, or if i only used the slabs mod, so it seems to be a compatibility issue

[Micalobia]

Did you update a 1.16.5 world that had my mod, to a 1.18 world that also had my mod? That might just outright delete any vertical slabs you had in the world, versions 2.x.x and 3.x.x are not very compatible, for technical reasons.

Also, is this what you mean by Fixed Waterlogging?

[ModMan2021]

Did you update a 1.16.5 world that had my mod, to a 1.18 world that also had my mod? That might just outright delete any vertical slabs you had in the world, versions 2.x.x and 3.x.x are not very compatible, for technical reasons.
Also, is this what you mean by Fixed Waterlogging?

Yes, that is the mod
It was a 1.16.5 world with the mod installed previously, but the vertical slabs weren't an issue as there werent any in that specific build