I don't know when this problem started, but whenever I put the PowerPoint app into Android Split Screen mode, PowerPoint becomes read-only and I cannot edit anything. When I quit Split Screen mode, editing immediately becomes available again. I have an active Office 365 subscription and I am properly logged in to the account in PowerPoint. Word, Excel and OneNote do not have this problem at all. I remember that when I last tried a few months ago, I was able to edit when PowerPoint was opened in Split Screen. My phone is a Google Pixel 2 running Android 9.0 Pie. Please rectify the problem.