Yes, in my opinion, this is the worst thing that Discord has to offer. Attempting to delete your phone number only results in you being locked out or having to input a new one. I was prompted to provide my phone number when I saw the “your account looks sus” notice, and I am unable to remove it. Since they will know my number if my account is hacked, I believe this may also be a security risk.
Just now, I tried removing mine because of this thread, and it worked perfectly. I used my phone’s app to do it. Entering my password was all that was required of me.
In my opinion, you are experiencing problems deleting your phone number from Discord because it sometimes requires a phone number for account verification, especially if suspicious activity is detected or if you’re a member of certain servers.