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!

[dsimeonova]

Hey @jaysadie !
I guess you've probably checked that but still wanted to ask you:
Did you check if this occurs at the moment where your underlying data is being refreshed?
Did you see any similar behaviour when consuming the dashboard from Looker itself?
Can you share a screenshot of the file of what exactly appears?

[jaysadie]

Hi @dsimeonova 

Thank you for your response.

Answers to you questions:

1. The underlying data changes once per hour. The schedule runs 30 minutes prior to the refresh. Also, all the charts on the dashboards pull their data from the same table.
2. When consuming data from Looker itself we do not get this issues. Only on scheduled dashboards. We also experience this when downloading the dashboard as a PDF.

Below is a screenshot that shows one of the custom charts being blank. It is not always the same chart that is blank. Sometimes it's the first chart. Sometimes the third or fourth. On rare occasions there could be two blank charts. In most cases all the charts show correctly. As mentioned in my first post, nine out of ten times all charts show correctly.

[jaysadie]

Hi @dsimeonova

Have you had time to review my response to your questions?

Thanks!

[dsimeonova]

Hey @jaysadie 
I was trying to reproduce it but i don't have the config that you are applying over the charts so I don't find the issue. Can you confirm if this happens on all types of visuals? Or only over specific ones? If that's the case is it possible to share the highchart config that you've used in those that is failing? If there is any personal/private info, please omit it or mask it.
I have some things on my mind that can be causing it but i need to see the code that you're using 😐 in order to test it.
Although I will share them in case if you already test them:
- Did you try to disable the animations from the Highchart config?
- Add a transparent background to the Highchart config?