Anti-Ice fluid frozen on Airframe
Had a nasty incident out of YUL some time back. Anti-ice fluid didn't flow off during takeoff. Was frozen to fuselage and wings. Almost had a tail strike during lift off, followed by struggle to get to cruise alt, increase in fuel burn leading to panic and hasty coordination with ATC to find a way to make destination with enough fuel.
Was a two step procedure. Anti Ice was type 4 at 100%. Light snow, temp around minus 2 degrees. Aircraft is composite not aluminum.
Went back to YUL a few months later and had to have the two step done again, same fluid, but no issues that time around. Roughly similar met conditions.
Anyone have any experience/idea of what could have caused the fluid to freeze to the aircraft?