Hi,

It seems at a quick glance that you are using the interrupt on change feature on portb. This means you trigger an interrupt on every change on portb<4:7> . In plain english on every edge , a press or release of the button. So the program is jumping into the routine. Without rewiring your circuit you can disable the interrupt altogether in the interrupt routine and then clear flags and set the interrupt in the main loop.

BTW its 22:05 here and time to go home so signing off now.

Regards

Sougata