You could be right, however, most of us members on S4GRU have used Sprint for years. We were not users of T-Mobile. Do we really know how many screw-ups they had combining other networks? We were not there using it.
PRL isn't just for roaming. It's for native CDMA too. If you didn't have a valid PRL then you wouldn't be able to use CDMA. It basically says "these sites are native, these are roaming, try them in this order and prefer this group over this other group". You can also try the #*#*72786*#*# dialer code. That will wipe CDMA provisioning and force it to run again. But like I said, as long as CDMA works, I wouldn't worry about it. Sent from my Pixel 4 XL using Tapatalk