Kerbal Space Program

I built a vehicle in orbit to go to the Mun and back. That worked without a flow. The problem started when trying to decouple the final stage. After decoupling, the vehicle became completely unresponsive to control inputs even though there was enough power.
Also, the orbit was messed up (see video below) and the log showed about a million StackTrace entries:

[LOG 12:13:52.374] dT is NaN! tA: 6.27323280732056, E: 0, M: 0, T: NaN
at System.Environment.get_StackTrace () [0x00000] in <ad04dee02e7e4a85a1299c7ee81c79f6>:0
at Orbit.GetDTforTrueAnomaly (System.Double tA, System.Double wrapAfterSeconds) [0x00000] in <f8bc9e2b903e48a5b248ab0083c07c62>:0
at OrbitTargeter.UpdateNodesAndVectors () [0x00000] in <f8bc9e2b903e48a5b248ab0083c07c62>:0
at OrbitTargeter.LateUpdate () [0x00000] in <f8bc9e2b903e48a5b248ab0083c07c62>:0


I made a short clip highlighting the issue:
https://www.youtube.com/watch?v=0qUyGQ_oId4

Links to the log file and quicksave file, since I cannot produce a .craft file - it was built in orbit with EVA construction.

• Quicksave: https://drive.google.com/file/d/1i8n2-w9CD0GsYGxYM2Xlxf5fTPQtn4FG/view?usp=sharing
• Log: https://drive.google.com/file/d/1wlpu1HONETXlod6dBurEKVjKfzeumoRh/view?usp=sharing

It might be related to this issue:
https://bugs.kerbalspaceprogram.com/issues/26926
But in my case when I rebuild the vehicle in the VAB, it works without a problem.