Basically a long while ago, Tapas updated their Terms of Service (and announced it to boot). A week or so later, controversy stirred up surrounding a certain clause that meant basically if you tried publishing your work through another party, either as a physical book, film series, etc. Tap would have the right to step in to see if they can't make a better offer to you first.
People were iffy on that. There was a bunch of twitter outrage and so forth. Many creators left Tapas after the event, feeling the site could no longer be trusted.
Note, Tapas did apologize with an explanation of where they were coming from and amended the ToS, getting rid of that clause.