Teams on iPad OS cannot open Office Files
Teams on IPad OS beta 13 cannot open most Microsoft Office files within the files section. It states that they are unsupported file types. Word, Excel and PowerPoint documents affected. OneNote seems to open though.
This is a known issue with iOS 13 beta, and we are working on a fix.
A temporary work around for me is to open my Teams files with the SharePoint app. Two apps vs one to get work done but at least I get to keep all the other coolness (mouse support) of IPadOS 13.
Great news, thank you for confirming this is being worked on. It is part of being on BETA software, just like to get ahead of the curve before it becomes main stream to support.
Robert Middlebrooks commented
Microsoft documents in the files tab, as well as other formats like PDFs are not being recognized in a open or preview mode.