Some recipes do use fluid tags. Some don't, and only work with CBC fluids. It would be better for compatibility if all recipes used tags. I'm also not sure the c namespace for mod-common tags is very popular compared to forge, for mods using Forge.

Seems like I missed a beat on these ones, will fix them

also: must've messed up the system I was using for tags in 1.20.1 datagen, as that exclusively uses Fabric but has a flag to switch Forge and Fabric DG.

Fixed in latest indev version and will be closed on the next release.