Not really a contradiction.
Slaughter withdrawal for a dose of Resflor (at proper dosage & route) is 38 days.
ONE dose of flunixin(Banamine) given IV has a 4 day slaughter/36 hr milk withdrawal.
It is not approved for IM administration - the route that many 'producers' administer it - so no 'approved' slaughter withdrawal time... but if you gave ONE dose IM, FARAD recommends at least a 30 day slaughter withdrawal. More than one dose... who knows, and you're on your own.
Flunixin is one of, if not the most common, offender for residues in slaughter animals... and to a large degree, due to use in cull (mostly dairy) cows going to slaughter.
Flunixin/banamine is not water... but I've seen myriad recommendations for its use on this and other boards by participants who treat it as though it's as innocuous as saline.
Have I given Banamine IM?... absolutely, but I'm also aware that it does cause muscle tissue damage, and that tissue residues are a concern.