Single Discoloured Leaf

Mutation. Keep it up

These things happen from time to time and are nothing more than a weird leaf. Unless there are many leaves showing these symptoms, it is unlikely to be a deficiency or other health issue, as these two things will show up in multiple leaves, not just one leaf. It is usually caused by a vascular problem, leading to a situation where the health of the chlorophyll can not be supported, leading to the yellow colour. Since it is only one leaf, you really don't have anything to be worried about. Hope this helps, Organoman.

Hello fellow grower it doesn’t look like any deficiencies or excess of nutrients. Could be the plant starting to cut it off an slowly pulling out the usable nutrients out to put it to other leafs or new growth.