A Tale of Ladies at Hastiludes, 1348

In those days a rumor arose and great excitement among the people because, when hastiludes were held, at almost every place a troop of ladies would appear, as though they were a company of players, dressed in manly equipment of striking richness and variety, to the number of forty or sometimes fifty such ladies, all handsome and beautiful, though not of the kingdom's better sort. They were dressed in parti-colored tunics, of one color on one side and a different one on the other, with short hoods and liripipes like cords about about their heads, with belts of gold and silver clasped about them, and even with the kind of knives commonly called daggers slung low across their bellies, placed in pouches from above. And thus they went on fine destriers and other well-arrayed horses to the place of the hastilude, and consumed and spent their substance, and wantonly and with disgraceful lewdness displayed their bodies, as the rumor resounded among the people.

And thus, neither fearing God nor blushing at the outcry of modest people, they slipped the traces of matrimonial modesty. Nor did those whom they accompanied consider what grace and outstanding blessings God, the fount of all good things, had bestowed upon English knighthood in all its successful encounters with its enemies, and what exceptional triumphs of victory He had allowed them everywhere. But God in this as in all things made a marvelous remedy to dispel their dissolution, for at the times and places appointed for those vanitites He defeated them with cloudbursts, thunder and flashing lightening, and the fury of diverse astonishing tempests.

Knighton's Chronicle, translation Will McLean 2013

Other translations have the ladies "dressed in men's cloths" or in "the cloths of a man" but that's not really what Knighton's Latin says.

He condemned the ladies because:

They wore the manly equipment of daggers, stowed in a particularly phallic way.

They displayed precious metal ornaments and horseflesh that they could not afford

They wore parti-colored clothing which made them look like minstrels, who were not nearly as respectable as proper ladies.

They wore hoods with liripipes, which Knighton might have scorned either as masculine dress inappropriate for women or because he thought liripipes were useless ornamental frippery.

Knighton is pretty clearly repeating a rumor: note the absence of the locations of any of these hastiludes. 

I can imagine a pretty prosaic kernel of truth to Knighton's account: some ladies go to a tournament in the newfangled fashions that the older generation doesn't approve of, and some of the ladies are wearing their husband's daggers while they are on the field so they don't get lost or stolen, and the event is spoiled by bad weather. And a Friar goes home and writes a sermon about it, exaggerating for effect, and reuses it every stop on his rounds and the tale grows in the telling.