sparkline charts not rendering in PUC 5.3, using PRD 5.3

Greetings. I installed biserver5.3 and published a report (using PRD 5.3) and the sparkline charts are not showing up.

They same PRD file (using 5.2) does work when publishing to a 5.2 biserver.

Thoughts on what I can check? All installed Marketplace items are 'up to date'

Thanks!