Tabs short code has problems with certain iframe content

I’m trying to create tabs at this page: https://medellin.ecocitizenworldmap.org/wuf7/

All 4 of the content areas are iframe embeds, but the first two only work when they’re active. In my current set-up, the “Esri GIS Ecocitizen Map” tab is not active and creates this error message: “Unable to create map : “d is null”

Any idea where they problem may lie?

Thanks!
Sven