After I installed VampiresDelight, the survival mode backpack became transparent (everything worked fine in create mode), and it returned to normal after removing VampiresDelight.

There will be no crashes on the client side of the game...

That's weird. Vampire's Delight does nothing to vanilla GUIs. Could you please attach your mod list? I think that it might be a mod conflict if it's about adding and removing Vampire's Delight. It just looks like another mod doing that.

That's weird. Vampire's Delight does nothing to vanilla GUIs. Could you please attach your mod list? I think that it might be a mod conflict if it's about adding and removing Vampire's Delight. It just looks like another mod doing that.

I checked for a while and found that VampiresDelight and Modern-UI installed together with this problem. Remove any one at will and it will return to normal.

I have 140 mods installed, but only VampiresDelight is experiencing this issue.

Can you help me check the reason? I really like these two mods, thank you.
The game version is: 1.21.1 Neoforge Mod list

Not sure about that, but could you try disabling shaders and look if it works without and with them?

If it doesn't work, I suggest opening the same issue on Modern's UI GitHub.

Not sure about that, but could you try disabling shaders and look if it works without and with them?

If it doesn't work, I suggest opening the same issue on Modern's UI GitHub.

Disable Iris and the problem persists.

But strangely enough, I tried to install only Modern-UI, VampiresDelight, and the necessary mods, and the problem went away, indicating that there were other mod conflicts causing the problem.

Not sure about that, but could you try disabling shaders and look if it works without and with them?

If it doesn't work, I suggest opening the same issue on Modern's UI GitHub.

I turned off the background blur in the configuration of the Modern-UI, and it became normal. I will turn off this problem.
Thanks for your suggestion.