I think some responders are only reading part of the thread to answer the "new cyl" question...
The bench bleed suggestion is prob. a guess that it got SO dry that that procedure might help.
I USUALLY vacuum bleed, but sometimes need to pump a bit as well, each method (pressure, vacuum & pump) has "tricks" involved to make it work better and if not done "right" might leave some air in the system.
SHOULD be a simple procedure, but often needs to be done twice or with the right "tricks" to get it done satisfactorily.