In 2014, former Tinder VP Whitney Wolfe, who previously had a "cofounder" title (and would later go on to found Bumble), sued IAC and Match over sexual harassment from another Tinder "cofounder" Justin Mateen, who is one of the plaintiffs in this lawsuit. (I put "cofounder" in quotation marks because it was an internal project at IAC and the history is a complicated.) Mateen was suspended and the lawsuit was settled for $1M.
https://www.washingtonpost.com/news/the-switch/wp/2014/07/01...
https://techcrunch.com/2014/07/09/whitney-wolfe-vs-tinder/
http://valleywag.gawker.com/every-fucked-up-text-from-the-ti...
Earlier this year Match and Bumble both sued each other in the midst of an attempt from Match to acquire Bumble. I am a little lost but I think Match / Tinder sued for $450M for patent infringement and Bumble countersued for $400M for using the lawsuit to make them look less attractive to potential (non-Match) acquirers?