This is a fairly routine move for a non-contender at this time. Reds did the same with Eugenio Suarez.
If Robert is claimed, it's a win-win. Mets save one month's worth of salary, and also save his $2M 2027 buyout. Robert gets to finish the season with a contender.
If Robert clears waivers, as he likely will, then it's probably a non-event. He will likely just play out the season as a Met. It's possible the Mets would release him, but there's no reason why they should.
David Stearns has given y'all some reasons to rip him over the last two years. This is not one of them.