I do not know if it played a part on this or not but in a Finnish podcast run by a NHL commentator and Kimmo Timonen, Filppula said he had hard time with the weather in Tampa. Not like he couldnt handle it, but to some Finns that kind of climate feels like you are just on a vacation in some tropical paradise which makes it harder to have the right mentality on playing the game right way. I bet some Canadians can agree on that as well. Ofcourse it's not the same for everybody.
For a reference in my home town where Barkov and Laine and others are from, the forecast says we get snow the day after tomorrow and the highest temperature during the day will be +2celsius (35.6℉). Obviously Filppula was already a NHL veteran, but i hope you can imagine what it feels like to some people be in place like Tampa when you have born and raised in such a different place. It can and will, to some people put their mind in a "vacation mode" which obviously is something you dont want while playing in the best league in the world.
Then again, thats on them and a flaw in their game if they cant focus while playing in any climate.