So the image displays in the browser as thumbnails (such as in the revision
history) and it displays fully when clicked directly on. But in this page
https://commons.wikimedia.org/wiki/File:Ecological_Speciation_(pollinator_isolation)_Schematic.svg,
the image does not display. It shows a transparent background typical of a
PNG or SVG and overlaid is the file name "File:Ecological Speciation
(pollinator isolation) Schematic.svg". This overlay text also displays as a
link. If you click the link, the image does display in full size.

I have not checked with another browser myself but I sent the link to my
friend and asked if he could see the image. He informed me that he was
seeing exactly what I was seeing.

I have not bypassed my cache but I have cleared my cache and purged the
page.

Let me know if you need anything else.

The Thumbor error is CommandError: (['/usr/bin/rsvg-convert', '/srv/thumbor/tmp/thumbor@8818/tmpcObLVI', '-u', '-f', 'png', '-w', '800'], '', '', -11).

Is it something with the image? Should I just re-upload a new version with a new filename?

This is a known issue where the librsvg version that Debian Jessie comes with segfaults when resizing some SVGs to specific sizes. Which is why some small thumbnails render fine and the bigger ones fail.

I don't know what properties the affected SVGs have that trigger the bug, I unfortunately can't recommend a workaround for this problem.

Resolution of this issue is blocked on upgrading the Thumbor server fleet to Debian Stretch: T170817