Here are some more details.
The amount of ram I've allotted for the 1.12 version is 1 GB.
The elevator only duplicates observer blocks.
If u guys need it, I'll provide the original (forge) world.
Ok attached a vanilla version of the elevator
Well, it is vanilla the mod  I have installed just helps in building, like filling gaps with blocks and creating walls with vanilla blocks, so it is completely vanilla.
I'll upload an archived version of the map later.
Hey, so i attached the world files. i have placed the player near the elevators. for some reason it wouldnt let me upload the wqhole folder so i had to send the files indiviually. If it dosent spawn u at the elevators, just look for 2 obsidian columns.
(also im running world edit forge mod)
Actually, they do not disappear after relogging and right clicking them dosent do anything... they become actual blocks.
I am currently not even able to get on my friends realm neither can he.