No on-screen pop-up for inbound calls

Dear all, lately I have noticed that when I am browsing on my phone/using apps while there is an inbound call, there is no pop-up for picking up the phone. The phone starts to vibrate, but I have to go through weird screen lock/unlock sequence to hope that the pop-up appears. Clearly some error.

This is going on for the last few weeks/months. At least since OS2.1, but maybe earlier. Not a major issue, but just irritating.

Current version: 2.2-t-202407157772-stable-fp4

Thanks for help & suggestions/.

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