Complete agreement on the latter - writers changing their minds is the glue that holds Star Trek together, as actual conscious attempts at continuity would be doomed to fail for the rigidity of such an approach...
Disagreement on the former, alas, as the "Breen = mystery" vs. "details of Breen culture and biology = common knowledge" discrepancy is quite blatant and divides our characters in two categories. (Perhaps luckily, any given single character seems unwavering in his or her personal stance, though.)
Whether the Incredible Evaporating Breen thing would be helpful or even interesting here... Dunno. It would
be deeply satisfactory for me personally to think that Kira saw this fantastic and unusual phenomenon take place in "Indiscretion", and shrugged it off as inconsequential to her down-to-Bajor goals - and then did it again in "What We Leave Behind", again failing to satisfy the silly curiosity of any of her supposed Federation allies.