Slack have confirmed on their status page that the issue has been resolved, and we have confirmed that Slack errors and latency are back to expected levels.

If you are still encountering issues, please reload Slack using Command + Shift + R (Mac) or Ctrl + Shift + R (Windows/Linux).

We'll keep monitoring for any further issues, but we're now marking this incident as resolved. 

We’re monitoring an ongoing incident affecting Slack. The impact appears to be mostly resolved, but we’ll continue to monitor until it’s fully stable. You can follow their updates here.