The three missions concerned are ;

Pherona spice courier needed

Perturbation agent needed

Survey escort.

I have completed all three a good number of times yet they are still showing. It may be the case that they are intended to be constantly available rather than lead to new missions but the mission description gives no suggestion of that. Either way I think it may be bug, or the text needs to be clearer.

I also note that the the survey mission works fine in static systems. However it is also available in dynamic systems where the player is sent to sectors where there are no bots to defend the survey from.

This has been fixed.

thanks