This sets up distrust in Lando from the moment you see him. Which is perfect - because he inevitably betrays the main characters.
No, he doesn’t.
He makes a deal, that vader latter changes, to save his friends and the population of his city while handing over one person, whom he doesn’t know.
Despite the deal being “altered”, he still manages to save everyone’s ass. Would stopped Boba Fett and saved Han too if the Lady and the Wookiee weren’t momentarily stupid. 3PO even knew what was up.
Technically I’d still call it a betrayal even if it was rational behavior on his part. I guess betrayal sounds a bit too harsh, so I’d amend it to saying that he deceived our main characters.