Couldn't reproduce villager trading problem.
As to piglins, I think it is intentional feature that mobGriefing false prevents mobs from picking up items.
If you meant that villagers don't pick up thrown bread, then it is NOT trading with them.
OK, there it is. Should I remove the first video?
Nvm, I already deleted it, but still have it on my pc just in case...
Hm, okay, if that's necessary, I'll just record this in 1.19.
Oh, right, I used it, but I'm pretty sure that I can reproduce it without OptiFine as well.
EDIT: I realised that I even tested it without, because originally I found bug in 1.18.1 with OptiFine, but also checked if this works in 1.19 without any mods before posting.
Oh, right, I didn't even realize you can do that I always just dropped them...
So either this report is invalid or we can't reproduce it.