Call icon faded, no incoming calls possible

Hello,

I had several times already an issue about the phone icon that's faded.

When it's faded, I cannot receive any calls. It remains so until I have pushed the phone icon myself.

It appears without any warning, and I'm pretty sure that I haven't done anything to launch this issue.

It looks a bit similar to an app being updated in background, but I can't imagine it's being updated like that...