There is quite a bit of debate regarding the recent PDO behavior. Some believed that the PDO did flip to a positive regime there in the mid 2010's, however, I think that was related to ENSO state then a PDO shift. But of course this can't be said with certainty. Cool phases tend to dominate for longer periods then warm phases so was it an abrupt flip to warm then cool or has ENSO state been a driving factor?