Heidelberg Windmill impression

Mine just started doing it; very stiff first thing in the morning, loosens up with use. Did you find a fix?

If the platen is not open then it will be difficult to take the impression off if not impossible it is not normal however for this problem to occur with the platen open ,you refer to the sheer pin so this must be an a3 platen ,some are a wee bit stiff to knock off but this shouldnt be difficult ,is the press full of crap in the lower shell?
Have you lubed all your internal oil pots?
if this is the small platen A4 same goes is the base of the machine full of crap ? Have you got your impression wound in to four or more? If you have ,replace the sheer collar you arent really meant to be working there its normal pressure reading ought to be 1or 2 .

Cleaned mine out, used a ton of wd40 on the moving parts, much better now.