I have a faq page with tabs. Clicking a tab normally selects that tab and shows the corresponding faq items. When using Cloudflare it accepts the href as a normal click and reloads that page.
I kept on searching and built up caching from the ground up. I used page rules to except various options and after that it worked again as usual. I could not pinpoint a specific cause.
So everything is back to it’s original settings and now it works as it should. Apparantly there is a ghost bug that occurs. It is not the caching plugin on Wordpress, that’s for sure.