Radbolt engine with empty oxidizer tank can not be launched.

Dear Devs,

I have a rocket with Radbolt engine.
Radbolt engine is at 4000 radbolts. Available range is 20 hexes.
I am trying to launch a rocket but the launch button is grey. 
Checklist has only one item - not enough oxidizer to reach out to desire destination. 
When solid oxidizer tank gets deconstructed launch is suddenly possible. (Solid oxidizer tank came from  setup for previous small petroleum engine rocket.)

As Radbolt engine does not require any oxidizer I see this as a bug.

Best regards,
Sheaker