Black printing long 7r

7R Hi my black is printing about 0.5mm long on the 1st side only. Black is position at front but end of the 450mm sheet it is long. Stock is 150 gsm long grain , colour sequence is y m c b. Prints ok on second side. Thanks in advance.

 

Please upload a picture what's going on. I didn't understand anything that you wrote.

 

Overall length of the black image is approximately 0.5 mm longer than the cyan, magenta and yellow on the first side only , the back or 2nd side has perfect registration. I hope this explains better.