The problems have 'retarded' the progress of the program.
mentally 'retarded'
(..) Gaston is running out of time. He's had his tries from horseback. Now he must try to end this on foot. "Retarded" means slow. Was he slow? No. Was he slow? No. Was he slow? (..)2017 Baby Driver
(..) upwards of $. What's his deal? Baby? Full cut, same as everyone. No, Doc, I mean is he, uh, retarded? "Retarded" means slow. Was he slow? No. Then he don't sound that retarded to me. (..)2017 Baby Driver