thanx to the Platform School Tutorial I could begin some humble experiments with Platfrom behaviour added sprites. Now as ladders are introduced, they began teleporting to (each other's x or y) positions !
Used Construct 99.95.
(i also tried physics behaviour, it behaved very strange.)
Thanx if you have some cure.
I found, if 2 events are removed, the error disappears, but of course no ladder movement will happen: