Strange behaviour of a LED bulb via SSR Relay: it's EMI?
Try to use 1K pull-up resistor with button, internal pull-up might not be enough to hold HIGH level with stronger EMI nearby.

Also set unused pins to INPUT_PULLUP mode (or OUTPUT) - they're floating after reset and it catches all kinds of interferences (if it's not a problem here it usually causes much higher current consumption by MCU).