[Q] [anyROM on 5.1.1] Bluetooth turning on ...

Hello community,

i have a massive problem with bt on my devices. As long as i stay on a 5.0.x (Sense) or 5.1 (GPE) Rom --> bt is working fine. I can start and stop as often as i want.
Searches for several days now to find a solution to get 5.1.1 working for me.

switching states results in a stuck of bluetooth turning on but never activate after several statechanges.
Doesnt matter if no pairs are build. if it is on it´s working fine. BT button doesn´t work anymore - no function when tapping on it.
Just showing 'bluetooth turning on ...' for hours.

This did not help:
clear bt cache
clear bt data
sometimes resulting in a full reboot (crash).
factory reset / wipe in TWRP
reset cache and or dalvik
try another 5.1.1 rom
tried aicp, viper, cm12.1, crdroid, pixel ...

Did it make even worse:
restart in save mode.
could turn bt off once from on state, never started after.

This did help a little:
using siliconvalleys kernel - it fells like the time to 'crash' (happens every few hours before) doubled.

Does allways work:
reboot / shutdown & restart - but this is uncool and makes the phone not usefull.

logcat - enteries when stucked:
err bt_hwcfg axi_bridge_lock aquire: Timer expired (62)
and some
err qr-netmgr-lib Processing rtm_newlink

I really would like to use a stable m7 with 5.1.1
Anone with a hint to solution?

regards

OT.