I'm not seeing any sticking on 2018/23541, and I've been using it for close to a week now. Maybe it's something you've installed? Instead of reflashing, you might want to try a hard reset and ensure no sticking. Then, one by one, install each app you are use, testing for sticking. Tedious, but sometimes the only way.
Re: PRL. First a definition of PRL from wiki.
The
Preferred Roaming List (
PRL) is a
database residing in a
wireless (primarily
CDMA) device, such as a
cellphone, that contains information used during the system selection and acquisition process.
In the stock rom somewhere under the start menu (can't remember if in settings, system, etc) you will find an "update prl" shortcut. That's the easiest way.
The other way is more involved, but can be done anytime. You need to kow your MSL (directions for how to get can be found here at ppcgeeks), then you can use the PRL shortcut found in Start>>Settings>>Phone Codes, after ensuring the following registry key is set thusly.
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DialParser]
"DLL-OEM"="PhoneCanvas.dll"
I believe on flash, DLL-OEM is set to ddcall.dll to enable 911 calls. Like I said, updating the PRL is much easier via the stock rom (lol!).