DayZ EXP 1.22 changelog tells us that the bug with batteries in head torches spawned on infected should be fixed now:
FIXED
- It was not possible to detach the battery from a head torch looted from infected
Now it could be me but after hours of playing EXP 1.22 I haven't seen a single infected that spawned with a head torch... Maybe this option hasn't been turned back on yet?