The timer for when you can manufacture again is missing for the conc railgun.

Instead of a timer, the mission just disappears.

This isn't a bug, it's by design. Concussion Railgun mfg missions have no timer. However many times you have done the prerequisite mission equals the number of times you can take the manufacturing mission, up to a certain limit (20, I think?). You could theoretically take 20 mfg missions for the Concrail in a row if you had the materials and had completed the prerequisite mission enough times.

It's like a see-saw; take the mfg mission, you are allowed to take the prerequisite. Take the prerequisite, you are allowed to take the mfg mission.

There is, however, a daily limit on the number of times you can take the prerequisite: 3.

Thanks for the explanation. I've checked my available missions and i dont really have a new one. Which missions do i have to take for the Conc? im UIT.

Depending on a choice you made earlier, it will either be "Covert Courier Escort" or "Transport Cargo Reclamation".

Serco will have "Cyber Solar Police" or "Weapon Design Interdiction". For the Itani it's "The Visitor" or "The Sower and The Reaper".

Thanks :)