Mk2 inline docking port is really weak

[Lyra]

I was making an SSTO earlier and I noticed that it was extremely floppy when on the runway, and when it got airborne the nose oscillated up and down and appeared as if the plane was nodding its head. I've had this happen before with a couple of other Mk2 craft, but could never figure out what caused it. Every single part was autostrutted to Heaviest Part. I tried re-rooting parts, draining tanks, changing flow priority, moving landing gear positions, changing the autostrut modes, and a whole bunch of other things, but nothing worked.

Then I swapped out the Mk2 Clamp-o-tron for an extra passenger cabin and suddenly there was no floppiness or oscillating whatsoever. I even flew it to the Mun and back with no structural issues. So it seems like the Mk2 port's nodes are really, really structurally weak.

Here's a picture of the craft. The Mk2 port was where the rearmost passenger cabin is. I tried replacing the Mk2 port on one of my older craft with this problem and what do you know, it was fixed too.

Anyone else experienced the Mk2 inline port doing this, or just me?

[king of nowhere]

the general solution for all structural stability problems is autostrutting parts. activate autostruts on all the parts in the central shaft of the ship, and there will be no floppiness.

 

P.S. that plane looks cool, but it does seem like it has too many engines