Today I found something strange in my WordPress, several of my posts had lost their tags. First I thought that it was just me, that I had forgotten to tag one, or two, posts, but then I realized that I remember adding tags to those posts. Then I found more untagged post, total 10 untagged posts, and I'm sure that all of them had tags before. So I wonder if this perhaps is a bug, could have been in 2.7+ and/or 2.8+, could it be an error caused by a plugin or maybe errors in the database? I was looking in an backup of my database, from before this summer, and their the posts, from before this summer, had its tags. Since I don't know exactly when this concurred first, I can't locate what might have been the problem. I have installed some plugin that display related post, among them YARP is the only one still using, that maybe can have caused it? What makes it more strange is that the posts, that had lost their tags, are scattered over time, two this month, one last month, three this summer, and rest before summer. None of them in row.