This is a severe Microsoft issue, in which any accounts under the age of 18 or 21* will be automatically logged out of various Microsoft login-based websites upon attempting to log in. Setting your age to over 18 or 21 should fix this. This issue doesn’t happen to everyone.
Keep in mind that this is the most likely issue, but there may be another issue present, though unlikely. This shouldn’t be a Mojira issue.
*It is either one, cannot confirm which.
Like what the user “Cries” said, it can be problematic to even look at. At this point, its a major accessibility issue as some users would have difficulty looking at something jittering like the ones in this bug.