Display problems after flashing stock FW Xperia V topic

I've recently flashed the stock rom for my Xperia V as described below for locked bootloader.
http://forum.xda-developers.com/show....php?t=2796554

Since then I face problems with the display/phone acting weirdly . About twice a day I can't turn the display back on (display unlock). In this state the phone actually freezes somehow. One strange exampled I've seen today: I received a mail message, with the set signal sound and notification LED. I wanted to check the message but couldn't turn on the display. So I checked if I can call myself with another phone but the mailbox turned on immediately. The notification LED was still active so I'm not sure if the phone actually freezed or not. The only thing I can do at this state is to remove the battery and restart the phone.
Another problem I've since flashing the rom is that when I start a call is that the display turns off immediately no matter if I place my finger/face over the proximity sensor or not. Funny thing is that the call can be held as usual, but after that I'm not able to hold the call as the display won't turn on until the call partner ends it. When he has ended the call the display turns back on. Right now I really don't know what to do.

Here is the history how the problem started:
- dropped phone on floor and display broke
- exchanged display
- I've had installed Xposed installer on external SD card and modified some things on the launcher. While I was waiting for the new display I've used the SD card in a different phone. This has somehow messed with the Xposed settings I assume.
- After I booted my phone with the new display in place and external SD inserted the UI crashed all the time and the launcher won't come back. So I've restored the system with the androids included function.
- This is where I first saw the above described problem.
- I've tried a different, modded rom. With this the display problem didn't occur but the battery performance was really bad.
- Installed stock rom from link above. Now problem with display present again. So maybe there is an issue with the original 4.3 rom?

Has anybody experienced the same issues as I do right now? I really don't know what to do but the problems really annoy me.

Thanks!