I drew what I call 'standard',
There is a missing resistor there.
Seriously, I have had this exact type of circuit resetting the mcu every time the button was pushed. And that mcu in question here was known to deal with interference.
I suggest that 1) you put back that missing resistor; and 2) if you have to go down with it, use a LOW-Quality (and I am not kidding here) button with high on-contact resistance. With a high-quality button, you run a substantially higher risk of resetting the mcu.