When revisiting the tracker after a while (1-2 hours might be enough), the site becomes unresponsive, because all JS rest calls are blocked by a captcha (screenshot in attachments). But when reloading my page, or even logging out and in again, I am not shown a captcha to solve. I have to delete all my cookies, to force a captcha to show, so that I can use the tracker again for a while (until the problem reoccurs). This happened to me both in Firefox on Linux and Chrome on Android.