Try other ROMs then. :silly:i just tried it again, i.e.
i wiped data/system/cache/dalvik and then re-installed XenonHD ROM (May-2018) + Magisk + Advanced Kernel
and i can replicate the GPS indicator fault.
the GPS icon in StatusBar stays ON, even when GPS is off.
when GPS is switched on/off, the icon just stays on.
when i reboot the phone, the GPS icon will disappear.
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edit:
i just wiped data/system/Dalvik/cache and flashed XenonHD (April-2018) + Magisk
and this time, the GPS icon does not even come on, on the StatusBar.
this is weird.