I used the MM patch and removed 4x PCB-1 from the ship, added them to a stock inventory and attached them. One of the 4 PCBs did not provide me with the option to "link" (no matter how close I am):

I have only 4x PCB-1 in my save and this one of them not show "Linked", so I assume it is this one:

1. Before using Construction Mode: https://gist.github.com/EoD/4eb4f1b0c1213a4eb21df027f9b202fd#file-before-using-construction-mode
2. After using Construction Mode: https://gist.github.com/EoD/4eb4f1b0c1213a4eb21df027f9b202fd#file-after-using-construction-mode

Here is the KSP.log filtered for "KAS". Unfortunately, it does only mention the other PCBs in there: https://gist.github.com/EoD/9552c27bab8bc1fdf3136f7e26ad0d4d

KAS is not compatible with the stock cargo system. There were glitches and unexplained behavior found when testing. There is a comment on the forum about it posted on December 26, 2020.

In nutshell, you cannot use the part because it stuck in an intermediate state RejectingLinks. How exactly it has happen cannot be explained at the moment. As a workaround, use KIS to attach KAS parts in flight. And remove the ModuleCargoPart module from the KAS parts to avoid further problems. Do not carry or attach KAS parts using the stock game functionality! As for the existing not working parts, I advise to trash them. Their state may be corrupted beyond repair.

@ihsoft I am aware that it is not supported yet, I just wanted to leave the note here as I thought you are looking for bug reports on 1.11.
I was able to make it attachable by overwriting the state though.
But I don't think any of them actually worked, at least when I messed around with it, they did not seem to do anything (the cable just stretched to infinity).

How do you suggest to trash them? It is part of a long-running station which I don't want to deorbit if I can avoid it.
Is it enough to store them in a stock inventory to "reset" them?

Thank you a lot for helping debugging it! I've put the note just to ensure you're not using this stuff in your carrier game.

How do you suggest to trash them?

The easiest way is to enable the debugging mode in KIS. This will reveal "Spawn" and "Dispose" options in the inventories. This is how I usually do testing in flight.

Is it enough to store them in a stock inventory to "reset" them?

Unlikely. The part's state is persisted when the part is stored. It may help in this particular case, but it won't work in general.

Ref commit 4971307