Yeah, the last time the west was record warm (in 2014-15), at least there was an easy explanation: It was a strong +PDO winter, with a warm neutral/weak el nino. Easy to see in that configuration why you would get a record warm west and a well below average east.
With the current configuration (-PDO/-ENSO/-IOD), there really is no reason why the west should be breaking their 14-15 records. You're not going to get anywhere near record cold in the east (like we did in 14-15) with that configuration.