I have received a mail from bugzilla telling me that the QAContact field of bug #202210 was cleared. The field X-Bugzilla-Changed-Fields: of the header of the mail contains the word "QAContact" almost 100 times, and the words "Security" and "Keywords" about 10 times. This repeated at least for one another mail, and yet another mail contained a shorter version: QAContact was there about 20 times, and "Security" and "Keywords" about 4 times.