I've seen this a few times and never thought anything of it, tbh.
As you can see in your clip, it's also not every vehicle just randomly turning 180°, but only you, the luchs and the pz; the others turn for 135°.
With that in mind, it's more important where they turn to and that's the center of the battlefield, aka. where the action will be going on / towards the enemy.
Personally, I believe that it's merely the game aligning the tanks after just putting them on the map.
Maybe the placement before the "flip" is a default alignment for a set of maps and the game then simply adjusts that for every map / game mode.
The player actually seeing this could be due to server-/game-lag.
Least that's what I make of it.