Its definatly the Beta with regards to saving on the external SD card I had the beta installed on my Honor9 and the save to SD card was also greyed out and inoperative. I uninstalled and reinstalled the non beta version… Save to SD card option not greyed out or inoperable, I can do screen shots if that helps
The Beta targets latest Android builds, where access to SD Card is changed.
Google does have a new method to access files in the SD Card but that would not work for map files.
The solution is asking for a very dangerous permission (full storage access), we are trying to get it approved by google. Basically we are asking Google for the permission to be able to ask the user for permission… LOL
You can thank google for those changes.