[OS X TeX] A real mistery

[Stefan Evert]

> On 22 Feb 2021, at 04:01, Ross Moore <ross.moore at mq.edu.au> wrote:
> 
> The label A is not actually in the file; at least not anywhere that I could find,
> using Acrobat Pro and Illustrator CC.
> 
> Try Zooming-in on the A (using Preview, say).
> The A disappears.

It doesn't disappear for me (e.g. with Preview), but it becomes a blurry pixel image while the rest of the figure remains sharp. 

> So I think that there must have been a preview added to the file,
> which is used rather than a complete re-rendering, when the image
> is viewed within a certain size range.

My PDF reader says that it's a stamp annotation. Not surprised that tex won't include annotations on a PDF image in the document.

Best,
Stefan