Strange issue with missing Font on Tumbeweed

I run a KDE desktop on my two TW installs and one 1 Leap install. I have one page in Firefox which doesn’t display the characters properly on one TW install so I assume I’m missing one Font but the problem is finding which one. The data should be W/M² displayed and is correct on all but one TW install. That one shows
WS3910solar

Anyone any ideas please?

Stuart

You can use Firefox’s developer tools to find the font. Right click on the element → Inspector (or something like that, I’m using the Spanish version): on the right panel you’ll find which font is being used.

That’s great but this page refreshes every 4-5 seconds so it keep resetting what I’m looking at. I tried the blockautorefresh in conifg but does not stop it!

Stuart