I wonder if it's a bad interaction between one of this person's extensions and Tumblr. Presumably if this were a problem for everyone, new blot posts would have

I wonder if it's a bad interaction between one of this person's extensions and Tumblr. Presumably if this were a problem for everyone, new blot posts would have cratered and Tumblr's SRE would have been notified and any recent releases would have been rolled back. So I would assume this issue affects only a small fraction of users. Could be wrong but I guess we will see.