Connected parts don't stay together

I needed a rope, so I created one by using structural panels and connected them using rotators with the bare look, with range of rotation restricted to something like 50 degrees. I connected the rotators alternatingly vertically and horizontally such that the rope can curl both horizontally and vertically. After connecting them I had to rotate the connected panel to the right orientation and I moved it a little such that the panels are in line and such that the panels can rotate without touching each other (the small thick end points of the panels are only there in the editor).

Now, in the simulation I pulled on the rope from the left side, and on the right side there is some small weight but it is not fixed, the whole rope can move freely. As you can see, the rope stretches: large gaps appear between the panels and somehow this happens only at the half of the rotators that are in the same orientation.

I see no way to fix this with the tinker options. Sidenote: I used the tinker panel to scale these parts down and made them weight much less or nothing, but other than that I didn't do anything strange.

I don't know what causes this. I tried to fix it by increasing the rigidness factor (or whatever it was called, from the tinker submenu) from 1 all the way up to 50 for these parts but it doesn't make any difference.