I think Kurt or Eric has reported this before. I have seven engineering Brigades on Mars to construct a prefab-PDC, But with six months to go the amount remaining to be built is 100%, the construction rate is 100.5 completion date October 2030. Looks like the ability of Engineering Brigades to construct Prefab-PDCs is still not working. I have managed to built a prefab-PDC on Titan, but there are construction factories contributing there, construction rate 107.8, completion date February 2030 for the second of a pair. Construction at both sites began at approximately same time. version is 5.14.
Regards.