Your interrupt routine at 0013H spans across several interrupt vector locations. I would suggest that after the ORG 0013h you place a LJMP to another location and place your interrupt routine there, then place a RETI at each of the unused interrupt vectors (who knows how many times we have inadvertently had our code trigger interrupts even when we thought we disabled particular ones?) Then begin your code a safe distance away from the vectors, say 30h or 40h.

Just my humble opinion
Hal