Kerbal Space Program

I am noticing a strange issue occurring in some cases when I try to add radial stages with Mammoth engines. To avoid the radial stages colliding with the central stage on decoupling, I place the radial decouplers near the tops of the radial stages, which should torque them so their tops rotate outward away from the central stage on detachment. However, in some cases, I am seeing the radial stages torque inward rather than outward; the decouplers appear to pull in rather than push out. This appears to occur when Mammoth engines are placed next to certain components (like 3.75m fuel tanks or other Mammoths). Removing the radial Mammoth engines or replacing them with Rhino engines causes the torque to work as expected.

• Expected behavior: radial decouplers mounted near the tops of radial stages should torque them so their tops rotate away from the central stage (as this guide explains)
• Observed behavior: in some cases, they instead torque the radial stages in the opposite of the expected direction, so their tops rotate inward, rather than outward
• To reproduce: construct a rocket with Mammoth engines on the central and radial stages at the same vertical level, with the radial stages attached via Hydraulic Detachment Manifolds near their tops. Decoupling should torque the radial stages in the opposite of the expected way. Replacing the radial Mammoths with empty S3-7200 tanks also triggers the inverted torque. I have also seen the same effect with Twin Boar engines.

I have observed this with no gameplay-affecting mods installed. Some examples demonstrating the bug (gravity hacked to show the torque more clearly, all radial tanks are empty):

• With Mammoths on central and radial stages: Torque is reversed from normal, and appears to be stronger than normal.
• With no engines on the radial stages: Torque is applied normally
• With empty S3-7200 tanks on the radial stages: Torque is reversed, but weaker than with radial Mammoths.
• With a Rhino engine in the center and Mammoths on the radial stages: Torque works normally; also works if the radial engines are replaced with Rhinos