Steps to reproduce:
I was deleting a chunk using World Stripper mod, and that chunk has rice crop

Logs
crash-2021-02-18_11.46.56-server.txt

After looking at the offending line in your log, it's right on updatePostPlacement. I check if the block isn't air to do a fluid update, but immediately disregard it to add a SUPPORTING state under it if the block above isn't RiceUpperBlock.

This might be hard to test, but would it work if I moved this state change into the isAir check?

I ran a local test and managed to replicate the exact crash you had. World Stripper seems to leave waterlogged, or watery, plants intact when stripping. I assume you tried punching rice and it crashed, right?

With the change I described above, punching the floating rice no longer crashes. I'll commit it soon; here's the screenshot of how the mod treats water plants. 😆

that looks good to me, thank you!