Of course, there might not be anything going on behind the scenes vis-à-vis a no-launch stipulation; however, if there isn’t, the question of why MNTA hasn’t asked for a TRO remains unanswered.
Perhaps another possibility is that they don't think they could meet the requirements absent some discovery. Unlike the typical case where the patent protects the drug itself, here Momenta may need some discovery to prove they are likely to prevail on the merits. But in that case, you would think they would make a motion similar to what they made (but which was rejected) in the TEVA Lovenox case 26 days after filing the complaint, seeking expedited discovery. However, that was denied, the court citing three factors; (i) they had not yet filed a motion seeking a preliminary injunction, (ii) they had offered no proof of irreparable harm and (iii) they had not agreed to mutual expedited discovery that TEVA suggested in response to the request. Perhaps they could do better in round two.