I've tested all controllable objects
[TABLE="border: 0, cellpadding: 0, cellspacing: 0"]
[TR]
[TD]Small Wheel[/TD]
[TD]| No issue[/TD]
[TD]| Piston[/TD]
[TD]| Toggle is unset[/TD]
[TD]| Flamethrower[/TD]
[TD]| Hold to Fire is unset[/TD]
[/TR]
[TR]
[TD]Steering Hinge[/TD]
[TD]| No issue[/TD]
[TD]| Spinning[/TD]
[TD]| No issue[/TD]
[TD]| Water Cannon[/TD]
[TD]| Hold to shoot is unset[/TD]
[/TR]
[TR]
[TD]Steering Hinge[/TD]
[TD]| No issue[/TD]
[TD]| Grabber[/TD]
[TD]| Grab Static Objects is unset[/TD]
[TD]| Cannon[/TD]
[TD]| No issue[/TD]
[/TR]
[TR]
[TD]Large Wheel[/TD]
[TD]| No issue[/TD]
[TD]| Rope Winch[/TD]
[TD]| Start Unwound is unset[/TD]
[TD]| Shrapnel Cannon[/TD]
[TD]| No issue[/TD]
[/TR]
[TR]
[TD]Powered Cog[/TD]
[TD]| No issue[/TD]
[TD]| Decoupler[/TD]
[TD]| No issue[/TD]
[TD]| Grenade[/TD]
[TD]| No issue[/TD]
[/TR]
[TR]
[TD]Contractible Spring[/TD]
[TD]| Toggle is unset[/TD]
[TD]| Flying Spiral[/TD]
[TD="colspan: 2"]| Automatic is unset[/TD]
[TD] [/TD]
[/TR]
[/TABLE]
The issue appears to be the block toggleable setting is unset when either uploading to, or downloading from the steam workshop. Key bindings and slider values are maintained correctly.