InunekoKyo Hmm… my guess is that there might be a bug where trying to update a column and delete it at the same time makes it fail.
If it's convenient, can you try this:
Press F12 in your browser, to bring up Developer Tools
Switch to the the "Console" tab:

Post a screenshot of the Console tab.
I can also try to see if I can reproduce the issue on my computer 🙂