Tags disappear from random question

Hi, I am a Math teacher. I have created a lot of questions for different courses. Since some issues are taught in different years I have created tags to choose in which courses I will introduce this questions.

Last week I made a quiz with random questions. For one of them I chose the top category in my course and all its subcategories and used the additional tag A. When the students took their exam, the tag A had disappeared. Therefore, my students had random questions, not corresponding to their course

I am not the administrator of my site and, I don't know which Moodle version I am using. It is the one used by Consejería de Educación in Madrid (Spain). I have e-mailed to the administrators of Consejería de Educación and they told me that the bug persists in the next version they are going to install.

So, is this a known bug/error? Has it been solved?

Thank you.