Tropicals & Tender Perennials: Deficiency or excess?, 0 by Hellobebe

Hellobebe wrote:
This is a leaf that I cannot for the life of me figure out what is going on with.
Brug was in mostly shade earlier in the summer, moved to more sun a few weeks ago (til maybe 3 o'clock.) . Leaves have been getting an overall lighter green color than when in more shade, and now, over the past few days, this has appeared on 3 of the biggest leaves. Notice the tiny dry looking speckles too.
I fert with either Peter's 20-20-20 or special miracle grow 15-10-15, about once a week.
She lives in a container with pro-mix.
I have read the recent threads re:deficiencies etc, but my little brain is starting to smoke from confusion.
Any help is greatly appreciated!