Ultimaker 3 / Print Core AA is postionited too high due to the black tab being stuck

[Manju 0]

Hi,

 

As soon as print core AA is unloaded, it seems perfectly normal. But when loaded back in, the black tab is continously lifted up and won't get down in its usual resting position. Thus, the whole print core is positioned too high - compared to print core BB - causing the print to fail every time. Does anybody know what the reason could be for that kind of failure? I would appreciate any kind of help. Thanks in advance!