Delayed Voicemail Delivery on iPhone 15 Pro Max, iOS 17.5.1 ? Related to Live Voicemail or 2nd iPhone?

I have been following the previous thread on this topic where there was blame shifting from Carriers to iOS. Prior thread had reports across numerous carriers, and I agree with general consensus on prior thread and think it is an iOS bug still present as of 17.5.1 (June 2024).

Delayed voicemail delivery has happened about monthly for me for about a year. I observed a call coming in yesterday (Jun 11, 2024) and my phone is set up to have Live Voicemail and Silence Unknown Callers : ON. I was tied up with another task and did not answer yesterday's call immediately. I noted the phone informing me that the caller was leaving a message and asking if I wanted to read a transcription in near real time. Neat feature, I thought, but I did not accept "real time transcription" option and let the message flow to voicemail planning to review it in a few minutes once I was free.

I returned a few minutes later intending to read and/or listen to the voicemail. The inbound call was listed in the "recents" panel but no voicemail. I checked periodically throughout the day for the voicemail but it was not listed. This message ended up being a relevant and time critical scheduling call from an office that is very difficult to contact.

I periodically continued rechecking voicemails on my primary iPhone 15 Pro Max for the next 24 hours and then without new notification, yesterday's voicemail quietly appeared today (22 hours after the call came in). The prior thread on this matter was unhelpful, but this is almost certainly the same issue. Please re-open as a known bug independent of carriers.

There have been recent reports of similar problems from users using Verizon, AT&T, Xfinity Mobile, and others on the prior discussion. We suspect an unresolved iOS bug. I do own 2 iPhones, both linked to my AppleID but they have completely different phone numbers and SIM connection accounts with Xfinity Mobile. All software and firmware is kept up to date, and settings had been with stable configuration and phone is restarted weekly or so per prior post recommendations. Thanks in advance for any solutions or suggestions...