Dear Cliff
I resolved the issue, but probably more luck than doing something specific. I deleted all plugins and reinstalled the ones I needed, and now the problem is gone.
Maybe it is just the caching taking a bit longer to clear, maybe it was a conflict, but if others have the same issue I will recommend to re-install plugins, as deactivating was not enough in my case.
Anyhow, thank you very much for your answer!