Pressing the junk indicator does not create a black list; it only marks this one message as junk. To train the filter takes time, periodically marking both non junk and junk. This URL may be useful: https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages

Yeah, I've been doing that for several weeks now and still keep cropping up in the inbox and not automatically going to the junk folder. I was wondering if there's something about the Freebird stores email that defeats the junk settings. They are the only junk email that is consistently going to the inbox, my junk settings have been working for everything else.

Take special note of https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages#w_other-ways-of-blocking-unwanted-messages