With the line removed, it is heavily suggested that Lando has pulled a Luke Skywalker over the past 20 years and has given up on everything. He is rotting away on a desert planet, and hasn’t left it since he was with Luke.
I didn’t get that implication at all in the movie. Luke was clearly very dour, but nothing about the way Lando acts in his scene implies he’s “given up” or “rotting.” If anything he’s pretty jovial. Maybe he stayed on Pasaana because he kept looking for the wayfinder, or maybe he hasn’t been on Pasaana this whole time and just comes back occasionally. Heck, maybe he’s there to party at the festival.
The “transmission” line does help take some of the coincidence out of the meeting, and I don’t think its existence contradicts with the previous movies (TLJ specifically mentions the Resistance has “allies” not present in the movie, and Snap is not in TLJ but is in TFA and TROS), but removing it doesn’t damage Lando’s character if Hal wants to remove it.