Yea there is definitely more going on than someone needing to play better. My group once saw the yellow and blue sections explode at the same time. We also experienced what you show in that gif, as well as the game preventing movement for half a second followed by an explosion. If this was how all aoes acted surely we'd all be used to it by now and this thread wouldn't exist. Also every other mechanic in the fight seems to act perfectly. It's just this floor mechanic being buggy and inconsistent.
I'm glad other people managed to do it without issue, but I think some of the instance servers don't want to play nice with the floor mechanic so you get the above happening.
