When my command block displays a command, all commands disappear from the game and the player becomes unable to execute the commands afterward. What just happened here?

Nope, it is indeed after you view the command inside a command block

the command block will say the command is not found, then it also breaks in the chat.

Alright, I've tried to reproduce this bug, however I did not manage to succeed at doing that. Please elaborate more on how to trigger such behaviour. For your interest, I could use the /morph command (or really any morph mod commands) whilst having an always active and repeating command block in the background executing "/demorph @A".

Maybe I should also note that I only tried to reproduce this bug in my current dev environment, which contains the newest code for this mod and also the optimal forge version.

So, if this issue persists, please let me know.

Strange, as it's very very reproducable on my end

setup a command block, set its command to morph (entity etc)

leave the command block

execute it (successfully)

reload the world

try opening its console. it will error saying "error: command "morph" could not be found" and then if you try finding the command using chat (/ button etc), all of your commands are gone

your commands remain if you never open that command block's console again.

I was using an impulse block set to all default parameters (needs redstone)

aye thought so, that seems to be a thing a lot of modders have accidentally done in 1.16 forge haha.

close it when you feel, our project was finished a month ago via datapacks on my side but I hope your mod ends up better nonetheless

Alright, after about one month of being relative inactive, I've now started working on this project again. And I could actually reproduce your issue this time: I used the wrong event when registering commands, causing them to not be registered after reloading the world.

Anyways, I've now fixed that bug, and that fix will be present in the next release.