Thanks.
So, so one of two things is happening…
1. The plugin is erroring and failing before the output is written out. But this seems unlikely – it takes the code (i.e. {{CODEletsferry}}
) and replaces it with your script. If it was failing, that code would still be there.
2. Something outside the control of my plugin is modifying page content.
Right now it looks like the latter but I have no idea knowing what.
That plugin version you installed adds HTML comments around the output and they aren’t appearing either – I was wondering if my plugin was just writing out empty content for some reason but, if this was the case, we’d still see the comments.
You may want to try and age-old trick of switching off all other plugins to see if that cures it and, if not, temporarily switching to a different theme for the same reason.