Strange Phone Numbers

Seems like lots of possibilities:

WiFi calling

I imagine that if you have blocked or curtailed your location on the Hungarian phone, it is picking something random. I have noticed this in the US too.

No idea. There was an individual in tow a few weeks ago who was usign some sort of European ESim in her phone. She tried to call me a few times but I never answered. Later I realized I had missed calls from all over the world ... again, it was her phone buy my phone was recording a different number from a different country each time she called.

Thats the only situation where this matters. If I see a call from Russia, I am probably not goig to answer it ... and it could actually be one of my kids in Kansas?

As the telecom possibilities became more complex, the reliability got a lot worse.

They no longer send your voice over a line. It gets digitized on your end then split up into the "IP Packets" that "Voice over IP" uses, sent to the termination point over the internet, out-of-order packets rearranged (the packets don't all go the same route), and then turned back into audio.

Of course when it's first digitized they skimp on it to avoid sending the higher and lower frequencies that "you'll probably not use" so they can save money on what they transmit. And they also compress/decompress the bits in each packet for same reason.

The only thing worse I've heard is if you ever listen to one of those "SSB Single Side Band" radios, where they do extreme compression but in a different way.

Long story but lesson learned is calls on the internet/wifi lead to strange results. About a year ago, after the company I worked for was acquired, the new owners gave us new phones (iPhone) with new phone numbers. Almost immediately I started getting regular calls (some as late/early? as 3am) but did not answer because I did not recognize the number. A few times the caller left voicemails, frantic, distraught, asking her son why he hadn't returned her calls. So I answered the next time she called to tell her she was calling the wrong number and to stop calling me. My phone number was "xyz" but her son's phone number was "abc." We had completely different numbers. She told me that she was able to reach her son most of the time but sometimes her call was routed to me. She was correctly dialing her son's phone number but my phone would ring when she called him. It turns out that her son was using a Google Voice phone number. The frantic phone calls continued for weeks. I asked our IT help desk for solutions. We decided to change my phone number. Something about VOIP phone numbers and weird things that happen when using them...

From my limited understanding almost all of "Voice over IP" is programmable. It interfaces with the telecom services. It's going as separate packets of bits over the Internet "on top" of the standard IP Protocol that all the data flow on the Internet uses.

Which means that every different part of the path, from one end to the other, is a good chance to be done by separate groups of programmers. They all have to hand off the signal to each other... in the right way with the right configuration.

You might guess at the possibilities.

(Including Bad Actors that exploit that. The phone number you see is also programmable. At different points in the path.)

edit: Should say Mr. E's mysterious number doesn't sound nefarious. The simplest I can think of (and there are others) is there's a lot of numbers in these programmers databases that are supposed to be cleared and reused for new connections. Sometimes that doesn't happen.