I have gotten (at least) three calls in the last week that did not show up on the phone app’s Recents list. The callers left voicemail messages, which is how I knew about them. There have been other missed calls where no message was left.The calls I know about were from friends and family, so no spamming was involved. In two of the three cases the phone happened to be right next to me, sitting on my desk, but did not ring.
As per a Geeksmodo article, I have tried restarting the phone, restarting the phone app, turning cellular data off and back on, and putting the phone into and then out of airplane mode, all to no avail.
I have had this happen numerous times over the past several years, on multiple phones and many different versions of iOS: a voicemail from a known number that never rang and doesn’t show in Recent calls. Sometimes the voicemail notification shows up immediately, but sometimes it’s minutes later.
I’ve generally written it off as a case were the cell connectivity wasn’t quite good enough for the call to actually connect to my phone, in which case the carrier automatically sends the call to voicemail, but the connectivity was good enough for me to get the voicemail notification. The way cell signals fluctuate is, like how most electromagnetic radiation fluctuates, a chaotic process that can’t be perfectly modeled or predicted, and this is bound to happen from time to time.
But I’m not a radio engineer, and I very well could be wrong. It just seems like a reasonable explanation to me. I do believe it’s more likely to be due to the carrier and the cell network than to any OS or hardware bug on the phone itself.
I also have had this problem for the past few years, 2 phones and multiple iOSs. I’ll be sitting at my desk with the phone next to me and I’ll just get a voicemail. I always figure it’s a carrier issue (which brings up a whole other topic of the reliability of carriers).
I kind of hoped it would go away when I got the 13 Mini a year ago but it didn’t.