Indeed, a huge surprise in Hungaroring and all the Ferrari fans around us, after Ham exit in Q2, remained shocked after Charles got pole. Was a confusion moment, since McLaren times in Q3 were around +0.5

So yes, the decrease in track temp but mainly the wind change affected the MCL39 and, as you said, they played safe.
Think this image summaries our boys feelings:
And sometimes, we as fans, are more upset than the McLaren drivers are
