Agree that it’s a bad look in this moment, but it’ll only be a big deal ultimately if the Cubs make it one. Happ has talked about this on The Compound podcast. The players get the business side. This stuff happens sometimes. I’ll still be surprised if they actually go to hearing, but it’s possible. The “deadline” was just the deadline to come to terms without filing numbers with the arbitrator. They can continue to negotiate right up to the point where they have the hearing.
I do find this interesting, particularly because the Cubs actually rarely go to hearings with guys, though the last guy to go to hearing was Ian Happ, the year before he signed his extension (Happ and Tucker are represented by the same agency, so relationships there are likely fine). The Yankees took Aaron Judge to hearing the season before he was a free agent. Hopefully they’ll come to terms with Tucker soon and ultimately deliver the bag, but we’ll see what they do.