In Ebon Raban's bridge fight, I blasted a hole in the bridge by the spike barriers, then had my engineer place new bridges while flying with the hoverpack. This made the bridges height 0 instead of height 3 to connect to the ground it was adjacent too. This caused the aforementioned weird movements.
Ohhhh--the engineer was flying over the water while placing bridge tiles?
Hmmmm. That's tricky. Engineers ordinarily build bridge tiles at the elevation they're currently at--if the engineer was flying over tiles of elevation 0, it's actually expected that that bridge would be built at that elevation! I'm not totally sure how to handle that, honestly. Maybe I need to make the game sample all adjacent tiles and try to pick one that's within 1 of the bridge tiles adjoining it? I'll have to think about this one.
Yeah, I later realized why it's working the way it was, but if you can resolve it to the highest altitude (since who would ever build a bridge under things) it'll probably meet most expectations. Using the 3 line bridge and underlapping an undestroyed segment of the stone bridge caused some visual weirdness as well.
Is there's any plans for a "Stair" contraption that's 1 altitude higher than than the land it's placed on?