For what it's worth, I've also been having some issues after the 1308 update.
The first thing I noticed was that my battery life had gotten noticeably worse with 1308. I assumed this was due a random background task eating battery and didn't pay it much attention, but after tweaking settings and re-tweaking settings and seeing no difference, I figured I'd check here to see if anyone else was having issues.
After reading about all of the LTE issues, I paid attention to my signal strength and hey! Where I once had consistent 4 bars of LTE at home, I was suddenly only seeing 1 or 2 bars of LTE that would randomly switch to 3 bars of 4G. Not cool.
I also paid attention to both my signal strength and battery while at work today and strangely, there seemed to be no issues there. 4 bars of LTE and no issues with data.
Clearly something with 1308 has altered the way that the phone interprets the wireless signal. I know the signal doesn't all of a sudden suck at home (my wife has an 8X that has no issues with signal strength). My phone drains very quickly at home because its constantly switching between 4G and LTE, typically displaying "no signal" while between the two. Lets hope Nokia figures this out pretty quickly, because it's pretty obnoxious.