This report[2] from October 2018 seems to indicate that Microsoft no longer does this:
> Ten to 15 years ago we were very focused on the competition between Linux and Windows,” says Microsoft’s chief IP counsel, Erich Andersen, in an interview with Yahoo Finance. “But today Microsoft is a very different company. With the rise of our Azure [cloud services] business, Microsoft has become one of the largest contributors to open source in the world. . . . We’re in a position where, as [CEO] Satya [Nadella] says, we love Linux. We love open source. That’s a big part of the future of our business.”
[1] https://google.com/search?q=microsoft+android+patent+fees
[2] https://finance.yahoo.com/news/microsoft-may-relinquishing-b...
Anyone with first-hand knowledge care to comment?