Non-issue; NVS/MNTA's lawyers are well aware of the filing requirements.
Probably - but there is definitely a disconnect between the timeline required by the appellate courts (see Rule 40 quoted below) and when the filing was made per Wheeler. Given that it is Momenta (fairly trustworthy) there is probably an explanation - but I wouldn't completely discount the possibility of an oops. Whole software companies exist just to prevent law firms from making such errors - but nonetheless errors do happen.
Rule 40. Petition for Panel Rehearing (a) Time to File; Contents; Answer; Action by the Court if Granted. (1) Time. Unless the time is shortened or extended by order or local rule, a petition for panel rehearing may be filed within 14 days after entry of judgment. But in a civil case, if the United States or its officer or agency is a party, the time within which any party may seek rehearing is 45 days after entry of judgment, unless an order shortens or extends the time. This time can be extended upon request, but the Fifth Circuit advises that such an extension should not requested “except for the most compelling reasons.”
Note that Rule 40 applies both to petitions for rehearing and for petitions for en banc.