New tacho card ..printouts

Hi ive just canged over to a new tacho card in the last few days and it works fine no problem
the odd thing is that when i take a printout it does a continous double print with the only differance being at the start of each
copy it says GEN 1 then GEN 2 is it the head ( stoneridge ) is it the card…?
ive not had the oppertunity to try a seimens tacho head yet … i await Answers with interest

I got a new card a couple of months ago , luckily change over between cards came on a holiday week , have noticed no difference between cards , including printouts