Kerbal Space Program

What happens:
When re-attaching parts using symmetry which have some action groups manually assigned, it looks like they stay assigned in editor (VAB/SPH), but actually only one part has action groups assigned after re-attachment.

• Start a new ship in the editor
• Pick some pod to have control and add a fuel tank or something to allow radial attachment with symmetry.
• Take a part that has actions which can be manually assigned to action groups, like an air intake.
• Enable symmetry (2 or more is enough) and attach that part to your vessel.
• Go to action groups tab and assign "toggle intake" (or any other action) to first custom action group.
• If you launch the ship now, all intakes will toggle with the action group (can be checked by right-clicking them).
• Detach the intake (all symmetry counterparts will detach too).
• Re-attach it back, using symmetry again.
• Launch.
• Press 1 to use the action group.
• Check intakes by right-clicking them. Only one will be toggled by the action group.

• This bug exists since 0.19 at least (I started playing at that version).
• Only happens with manually assigned actions, the default ones (like lights or landing legs) stay assigned.
• Also happens when the part with actions is re-attached indirectly, as a part of subassembly (think intakes/engines attached to wing when re-attaching wings).
• Very annoying with SSTO planes and solar panels.
• Windows 7 64-bit, but I'm pretty sure it's system independent, since it's a logic bug.

Workaround:
After re-attaching, in action groups tab remove all relevant actions and reassign them again. Each time you reattach part with symmetry which use action groups.