phone hang

With lineage-16.0-microG from download.lineage.microg.org at oneplus3 and z2_plus:

`Device only` works fine.
`Battery saving` hangs phone.

Start by reproducing the hang with lineage-16.0-microG on the listed OnePlus 3 and ZUK Z2 Plus devices, comparing the Device only and Battery saving modes. The issue names no source files or tests, so the first investigation must identify the Battery saving entry point and capture the failure. Done means Battery saving no longer hangs the phone on the affected devices.

Written by the indexing model from the issue text.