Hi, Newbee

Just open your PIC datasheet @ the OSC section, and you will discover the reset pin need a fast rising signal to act correctly ...
you also will find correct circuitry to pass by your supply lazyness ...

in other words, your supply is a bit slow when giving power, and the reset pin must be kept low till the supply voltage is established ...

that's why power supervisors like MC33064P / TC54 VN xx have been created.

Alain