About 10 days ago I installed a security update to the forum software that we use, Drupal’s Advanced Forum package.
Judging from the discussion forums associated with Advanced Forum, they mucked something up in a security update, so a lot of Drupal websites are currently being plagued by these errors.
It’s unlikely to be affected by which web browser you use. I think it’s fair more likely that it will occur on a few specific forum posts which unluckily happen to trigger this error condition.
Being free software, Drupal unfortunately tends to take its time about fixing problems, so I wouldn’t hold my breath for a quick fix to this. We do have the option to remove the latest security update if this becomes a really serious problem, but I’d prefer to avoid doing that if at all possible!