Brake drag with new caliper

Just fitted a new rear caliper to 1997 P38. Bled fine and working. However after a week it's dragging again just like the old one. Flexi hose breaking up internally causing fluid not to flow back or is there some hidden one way valve somewhere? (wouldn't think there is one but the P38 usually has a few hidden surprises).

Dont know about p38 but have had problems with flexis on other cars breaking up internally not letting piston go back.

Re-bled again tonight and seems ok. Will keep an eye on things.