Intermittent random blank dashboard charts in PDF deliveries via Looker scheduling

[jaysadie]

We have a number of Looker Dashboards that include a number of tiles displaying custom HighCharts charts. All these dashboards work perfectly on our multi-tenant portal. Most of our customers create schedules to have dashboards delivered to them via email at a frequency of their choosing. Almost all the time these dashboards are delivered without a glitch. Problem is that occasionally some of the delivered dashboards (in PDF format) show one or two blank charts out of five charts/tiles. This is not a user permissions issue, because the same user will get the dashboards delivered perfectly approximately 9 out of 10 times, but then one random delivery will have the blank chart issue. The very next delivery will display all the charts correctly again.

We've had numerous technical people work on this, trying to find a solution or workaround. We've tried changing timeouts and rendering delays, but nothing works. We've opened support tickets with Looker and used a consultancy company to try and resolve the issue. No matter what we try, the problem persists.

Is there anyone out there that has experienced a similar issue or has some advice on what else we can try? Any help or suggestions will be greatly appreciated.

Thanks!