I was trying primarily with open_gapps-arm-8.1-nano-20181014.
open_gapps-arm-8.1-nano-20180922. open_gapps-arm-8.1-nano-20180906 also.
I honestly do not remember the combinations I tried.
I was able to install without error, until I reproduced the error.
I know that sounds very odd.
Only since I flashed repit, rom and OpenGapps using USB/OTG.
Something seems to be dragging over from that one time.
I have been fighting the install since. (Using repit and OpenGApps)
Installing from internal storage or ADB Sideload.
What really confuses me is why Delta gapps work and OpenGApps does not?
Something in the installer script?
Side Note:
Currently installed.
Manual repartitioning.
flo-Classic_10-2018_AOSP_8.1.0_r48_OPM8.181005.003_followmsi
opengapps/open_gapps-arm-8.1-nano-20181014
So I know these two work together.