Runbox 7 spam filter isn't learning

In the last month or so it appears that despite my vigilant review and identifying items in my stream as spam, the filter isn’t learning. Items I marked as spam every day for the last several days continue to appear in my inbox stream with the identical email address as before, but the filter doesn’t eliminate them. Does the filter only run occasionally, like every week or so? It is frustrating to have to mark as spam everything over and over again, only to see the same miserable senders appear with identical sending email addresses a few hours or days later, and have to mark them as spam again and again. Is there some setting I need to make that I haven’t made? The spam filter used to be reliable, but in the last month or two it seems as though I spend significant time going through my inbox. What am I doing wrong?