Only had my M300 for a month and still testing everything. I have run into an issue with the 2.2.1.7 app running correctly on a Huawei Pro 10.8 M5 tablet. The 1.1.9 version of the app seems to work OK on the tablet but there are a few other issues that I won't get into now.  I have a friend that is having the same issues using the same tablet. The main problem is the mapping mode. When creating a map you have 4 types to pick from. The Waypoint and Linear Flight Mission opens fine although I have not actually flown a mission with either. The Mapping and Oblique will not open correctly. You get the initial light gray screen but no data entry points on the right side of the screen or map layout. I get the same outcome even if the M300 is connected and the tablet is connected to the radio. There are some other small issues with manual camera settings that can be except but the fact the two most popular mapping missions can not be accessed on the tablet is frustrating. Has anyone else had this issue?

I am having the same problem with the M300 and a Samsung Galaxy TAB S5e, is there a solution?

I'm not sure if the type of tablet or version of Android will make a difference but the fix for me was to go to the software download section for the M300 and get the latest version of the Pilot APK for the M300. It seems they have taken care of most of the issues I had. I don't think google play store has it. Just load it on the tablet and install the APK from the tablet. I have included the link below.
https://www.dji.com/downloads/products/matrice-300