Kristen Bicknell seems to have signed with Party Poker in the latter portion of 2017.
Here's a picture from a Party Poker event in May 2017. Notice she isn't wearing the patch, but the guy next to her is. This would imply that she wasn't yet a sponsored pro.
https://www.facebook.com/partypoker/...56102509699992
Now take a look at this article from flushdraw.net, dated January 31, 2018: https://www.flushdraw.net/news/phili...al-partypoker/
In addition to Haxton and Gruissem, partypoker has signed Jason Koon, Martin Jacobsen, Joni Jouhkimainen, Fedor Holz, and Kristen Bicknell all since September. That’s not to mention such names as Mike Sexton, Marcel Luske, Johnny Lodden, and Sam Trickett that were already on the roster.
Provided that author Dan Katz is correct about this, it means that Bicknell signed with Party sometime between September 1, 2017 and January 31, 2018. Since her tweet referred to "four years", it seems likely her signing was closer to mid-late 2017.
But even if she signed in early September, that still would leave her a bit short of 4 years. So why is she departing now?
My guess is that Party wasn't thrilled about the anti-vax stuff, and asked her to quit with the public statements about it. She probably refused, stating that she felt strongly about the matter. She and Party probably got into a stalemate about this, and decided to end her contract a few weeks early, and to say nice things about each other on the way out.
This is all speculation, but when someone's sponsorship contract seemingly ends early, and when that person has been involved in recent controversy, it's not hard to connect the dots.
Also, there was no other reason for them to part ways. She's Canadian (within Party's market), is still very marketable right now, and on her end it's basically free money. Unless she had another offer (which we'll know soon), it wouldn't make sense for either party to want to terminate association, unless it's about this COVID issue.
We will probably never get confirmation either way, unless an insider comes forward at some point.