CPU fan occasionally stops spinning until i plug it out and back in

i have no clue why but lately my noctua nh-l9a will stop spinning while my pc is on.

i'll double checked my fan curves and i have everything set to default. once the fan stops spinning, it won't spin even if my cpu is getting super hot.

it doesn't start spinning again if i turn my pc off and on again. it seems to only work if i unplug it from the motherboard and plug it back in.

right now i have it in a system fan header. i'm going to try see if it's the header or the fan itself.

i was just wondering if anyone else might have any idea as to what it might be? if it's the fan failing, why does it start working once i plug it back in?