Hi Kyle, thanks for your analysis, but what I do not understand is the following:
You say that it has nothing to do with CB but with my hoster. But why do I not have any issues with 'older' Joomla installations that run on the same hoster (but built with older CB versions)?
Here is the link to my production site (built with CB 1.9.1 and Joomla 3.3.6). This installation is set up in the same webspace of my Hosting package (but installed in a parallel subdirectory). (the URL I sent you yesterday by PM was my TEST site build with CB 2.0.13) :
[REMOVED]
login first in frontend. If you view a profile you see that ALL the tabs are rendered propperly, with Firefox, Chrome and Edge, so the only difference to my TEST-URL (see link in your email box) is the version of CB and Joomla
regards
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