Forum font increases in width/boldness if also installed locally

[ivarhill]

These forums appear to use Source Sans Pro in most places. I recently also installed this font locally, and ever since doing so it has increased in font width/boldness to the point of being much harder to read. Interestingly, when italic it displays at a correct weight, but otherwise is much too bold.

Is there any way this could be resolved aside from me uninstalling the font on my machine? I need it for other purposes but while it's installed the forums are a lot less legible. It's a shame since it's otherwise a fantastic font!

Attached a screenshot for reference!

 

[ivarhill]

Interestingly, this now seems to happen in the opposite direction instead. I see all text as non-bold, even text that's supposed to be bold. Very odd!