We've implemented a fix that should resolve the issue with PDF and PNG exports. We're monitoring the results to make sure this has the intended effect and will update this message as soon as we've been able to confirm this.
If you were impacted by this incident and were unable to export your mural, you will need to initiate the export again.
Note that a side-effect of this incident is that mural thumbnails were not being generated correctly. If your mural is missing a thumbnail, you can correct this by opening your mural and editing it. This will trigger a new thumbnail to be generated.