At first glance it looks like a javascript loading issue. You already mentioned the chart.js from Poll not loading.
Check the browser console (F12) to see if there are any more javascript issues.
Try to isolate the issue to a single plugin (by disabling plugins one by one) and hopefully you can find the origin of the issue.
We have several website where all these plugins are active at the same time and don't have an issue. If you find it, please contact us.
info@elgg.org
Security issues should be reported to security@elgg.org!
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