Apparently tumblr has started inserting full blog descriptions into post headers. This is causing a high number of false positives. I’ll update as soon as I can find an acceptable solution.
Update: Fixed in v0.4.11
v0.5.0 had a bit of a conflict with Tumblr Savior so I’m releasing v0.5.1 in hopes that it goes away. Sorry for the trouble and I hope you have a great new year.