Found what appears to be a recurring print defect on two 1966 series 5 cards. Both #371 (Stange) and #381 (Fischer) appear to have a yellow streak, as noted. Both of these cards are in column 9 on the print sheets. Other cards in this column include #379, 440, 410, and 437 but I haven't see that defect on those cards.
1966_371_STREAK.jpg
1966_381_blue_5.jpg