Servo Attachment Issue

[Ashandalar]

In the SPH, I have two servos (in mirror symmetry mode) attached to fan shrouds, and when the servos rotate, so do the shrouds, as expected. However, when I launch the vehicle, the servos seem to no longer be attached to the shrouds, and rotate independently of them:

I've built and rebuilt this vehicle three or four separate times, and this issue occurs consistently. Sometimes, only one of the servos rotates despite them being in symmetry (though this isn't pictured in the video).

This is my first time experimenting with robotic parts, so forgive me if this is a known issue. Are there any fixes / workarounds? This is in KSP version 1.12.3 (native Linux client) and no mods are installed, save for Making History and Breaking Ground.

[Ashandalar]

It seems that servos don't like being attached to this fan shroud in particular. I've found that a workaround is to attach something else to the servo, say a battery bank, and attach the shroud to the battery, then this gives the expected behaviour: