You mean forum home https://hardforum.com ?
I cannot reproduce this on:
MacOS via Chrome and Safari
iPhone 12 via Chrome and Safari
Android via Default browser
Looks like you have incomplete download before you open the forum/browser.
Does it happen all the time you visit the forum home?
I updated the forum software 3 days ago, including JS files.
Can you please clear your browser cache and try to re-produce it again here?
Or please try on incognito mode.
Based on your description, I cannot reproduce it myself.
I haven't seen any error logs this week.
Could it have ad-block support also?
Might be due to some amazon or similar affiliate links.
Could be an issue with Firefox only.
No changes or update on HF since few weeks.
I'll keep on observing for now.