I posted a bug report explaining this problem but I think this might not be a bug and that the plug-in for claiming is just outdated. I found a big, cool cave and decided to build a base there. I claimed the area and when I wanted to make a farm using pistons I found out that it doesn't work. A hint would appear that I should claim the area which I already did. I did some testing and found what the problem was. I claimed an area and placed two pistons with two Redstone torches powering them. The first piston was on y = 0 while the second one was on y = -1. In the following screenshot, you can see that the piston located on the y=0 block is working while the second one isn't:
View: https://imgur.com/a/GjbO7Uy
So claiming an area only actually claims all the blocks in that area from y = 0 to y = 256 instead of from y = -64 to y = 256. Maybe the plug-in is outdated so please install the newest version of the claiming plug-in. If there isn't a 1.18 version of the plug-in, maybe try configuring it somehow or choose another plug-in for claiming. I'll leave the solving of this to the developers of course but I fear that you won't take any action if there isn't a 1.18 version for the plug-in you are currently using.
So claiming an area only actually claims all the blocks in that area from y = 0 to y = 256 instead of from y = -64 to y = 256. Maybe the plug-in is outdated so please install the newest version of the claiming plug-in. If there isn't a 1.18 version of the plug-in, maybe try configuring it somehow or choose another plug-in for claiming. I'll leave the solving of this to the developers of course but I fear that you won't take any action if there isn't a 1.18 version for the plug-in you are currently using.
