Random photos delinked from albums

I am using lightroom mobile while traveling. This morning I went to export photos I had edited from yesterday and found many photos missing from the album--and it further dropped from 99 photos to 74 as I was selecting photos to export. The missing photos are still visible in “all photos," but most albums now have roughly 30-70 percent fewer photos than they did yesterday. What should I do? I really don't want to browse through the thousands of photos in" all photos“ to reattach them to hundreds of relevant albums