@rsoxhater thanks for reaching out. I run mine around 30 fps without issue, iframe set to match. To answer your question, reboots won't change frame rate but DO change / revert bitrate if using custom etc. Therefore don't think FPS is being affected by that. Now with that said, I have seen some weird and wonderful quirks of OpenALPR such as rebooting a 5231 and causing it to hang after it processed a stream. That was a bug in OpenALPR. I've also seen platform related quirks that potentially could change full settings (if you grant admin level access to the stream through the portal etc) but I run mine in a Docker instance, cam access locked down. If it isn't one of these quirks (which I believe it could be) then the only other suggestion would be to reset cam to default (to start fresh) and re-configure.
Out of interest, does this only happen with 45/45 or if you set to a 30/30 (FPS/iFRAME) it remains as set ?
If after all of the above (including the full factory default) doesn't resolve I would definitely a) reach out and let me know and b) report a bug through OpenALPR's community channel as well
HTH