Number of comments is erratically reported

Hi. It’s a relatively minor problem, however I’m unable to figure out why the heading showing the number of comments on a post is quirky.

What’s really confusing is that on this link the heading is correct:
https://www.digitalgeography.co.uk/archives/2005/12/the-amazing-magnalox/

whereas here it’s wrong:
https://www.digitalgeography.co.uk/archives/2005/12/google-earth-virtual-graffiti-using-a-gps/

and finally, it’s just missing here:
https://www.digitalgeography.co.uk/archives/2005/12/british-national-grid-overlay-for-google-earth/