Quick update: I’ve no idea. 
Picked five movies from my primary Plex server - all MP4s, with embedded cover art, and with requiredBandwidth = 2147483647.
Added the movies to a test PMS system where they’ve never existed.
PMS analyzed them and assigned correct requiredBandwidth values.
The movies had all been added within the last 60 days to the primary PMS to libraries using the new movie scanner. PMS on both systems kept “reasonably” up to date, meaning they’re running Plex Pass releases, but I might wait a week before updating to the latest release. Both are now on 1.23.4.4775.
Next Steps:
I noticed some of the MP4s had partially correct requiredBandwidths. The first one or two numbers were correct, but the remainder were 2147483647.
So, I’m wondering if maybe I was not allocating enough time for scheduled tasks on the primary PMS. Deep Analysis, which generates requiredBandwidths, runs as a scheduled task.
I changed scheduled tasks on primary PMS to run from 00:00 to 23:00 (test PMS has all of 10 movies, so time not an issue).
I’ll Plex Dance three MP4s with requiredBandwidths = 2147483647. Once Deep Analysis runs I’ll check requiredBandwidths and also pull log files (I don’t know if log files show anything about requiredBandwidths, I’ve never looked).
That’s where things sit now. I’ve some other things to check as well (movie in single vs multiple libraries, does local media assets or other library settings matter, etc).
Will update occasionally. Sooner if I find anything interesting.
Primary PMS: DS918+, DSM 6, PMS 1.23.4.4775.
Test PMS: DS414, DSM 7, PMS 1.23.4.4775.
