Stackers let you place their supports offshore, but they collapse when built.

I thought the supports would work like the way docks do or something, turns out that they don't

Steps:

1. load save
2. use unity on them (I didn't do it before the save in case you guys wanted to do something else with them)
3. Wait a couple seconds for them to build.
4. The rightmost three will collapse in about 5-10 seconds after the warning appears.

I had this issue today as well. It seems like something is wrong with the stability testing in planing mode

I have 4k hours and use stackers extensively just like this. I have never seen this error before U3