I doubt it’s anything attitude related for either one of them. As Plouffe said in the Skor North Twins podcast, sending them to Florida changes their environment. Before the agreement with the Saints to be the AAA affiliate, players at least were sent to Rochester, NY to change up their routine. Lewis and Wallner currently are living at the same place, same routine, etc. all that has changed is driving on I-94 west to St Paul instead of Minneapolis.
Has anything truly changed for Wallner or Lewis? The fans and media can both follow them easily to St Paul and continue to micromanage their performances. Sending them to FL allows a true reset and out of daily local media coverage.