One of my hives did this after I put in my Apilife Var Tx.
It was the second day (they bearded out on the first day but it was sunny so I left them).
In the afternoon they were in a soggy mess, some falling off the landing board into the grass.
I scraped them into a box and took them inside to dry and they were OK.
I opened up the floor a little and no more came out.
I think it was the thymol fumes.
lol I'm so sorry to laugh, but the way you describe it, I get these visions of hordes of little lady bees getting teargassed, and haring out of the hive, hacking and coughing, eyes streaming, falling about, leaning on walls and fainting into the grass ...