New to fig stewardship. I have leaves on a recently purchased Celeste fig that are browning at the edges. From photos I've looked at, I don't think it's rust (and it seems like the wrong time of year), but please correct me if I'm mistaken. The foliage on about half the branches (where the brown-edged leaves are concentrated) looks sparse compared to elsewhere on the tree. Any suggestions or diagnoses?
 

It looks like sunburn, is it only on the very first leaves? May not have been hardened off properly, so first leaves would be burned and subsequent leaves normal.

Another vote for sunburn.  Not to worry, new leaves will come in and replace the damaged ones.  It just takes a little time.  Even complete defoliation is ok.

i think that  isn't sunburn.
that;s fertilizer burn.
i suggest you flush the pot with water.
when you resume fertilizing, cut the amount in half.