I have a similar problem. There is an index file with maps. The maps end with the numbers 1, 2, 3, ..., 10, 11, 12, ..., 100, 101, 102, 103, ..... So Search Console shows from time to time only maps that end in 1. That is 1, 11, 111 are processed. The other maps disappear and I don't see their data.