After you /setblock a block where a cable/pipe was, the pipe is not completley removed. i stil exists but doesnt work anymore. it is not possible to lace a new pipe there, but you still can "connect" pipes to it. this still happens after manually placing another block there afterwards

/setblock correctly removes the pipe for me, must be another mod's fault.

You can usually resolve this issue by using this debug command after changing enableDebugCommands = false to true in the MI config : /mi pipes <pos> clear where <pos> is the position of the pipe in the world.

As a note - this is an issue with the Carry On mod (or at least it is for me using it in Prominence 2 in Aug 2024). I've logged a bug in the Github repo - it outlines the changes you need to make to the Carry On server config to disallow picking up wires, etc.