Hey there John, that's actually kinda funny right? anyway to answer your question, the plant has either too much or not enough N , if you're not feeding that's because the plant needs a bit more N, so it is cannabalising some fan leafs to find some. usually this will happen in vegetative stage. It's actually not such a bad problem, but it looks not great right? anyway if you have some on hand do add some N. if you've been feeding NPK with enough N then it's a lockout. Could be too much N so the plant stops absorbing through the roots, meaning that eventually it has to cannibalise itself same as a deficiency. Hope this helps ! 🚀