A group of Facebook client solutions managers have won conditional certification of a nationwide collective action to recoup unpaid overtime wages they say are owed them.

But Facebook estimates about 250 of Susie Bigger’s proposed collective group, more than half of the total number, should be excluded because they signed mandatory individual arbitration agreements, according to Judge Leinenweber’s March 22 opinion for the U.S. District Court for the Northern District of Illinois.

Those potential plaintiffs shouldn’t get notice of the collective action and should be barred from opting in, Facebook said.

Facebook’s Catch-22 is that it can’t yet ask the...