Originally Posted by Funk Wizard
Zero issues with the wakeup but yes sometimes prox sensor does not respond immediately like when answering a call with device on the face the light does not switches off immediately
Ahh. Light bulb moment. The 25R build didn't yet incorporate the proximity check when waking the device, this fix was implemented on one of the following builds to combat accidental wake gestures occuring in people's pockets. So basically, because the proximity sensor isn't involved when waking the device on 25R, you're not having the same issues that other people are having on later CM11S builds and later CM11 based custom ROMs. So for the moment you can probably get away with running that Lollipop modem (it really isn't the most ideal solution though, testing the other KitKat modems would be better), but if you decide to update at some point you'll definitely need to revert to a KitKat modem.
EDIT: Here's a link to the modems if you need them: