Src block fontification when scrolled off window

[Aaron Jensen]

Hi,

In one of my org files, I will occasionally see src blocks lose their
formatting. Specifically, if I switch to editing the src block, or I
first open an org file that is expanded to a section with a src block,
if the beginning #+begin_src is scrolled above the window, but part of
the block itself is still visible, the src block will be fontified as
if it were regular text in org. I have org-src-fontify-natively. If I
scroll up so that #+begin_src is in view, it fontifies as expected.

Is this expected behavior? Is there a way to increase the lookback amount?

Thanks,

Aaron