Logo in left sidebar does not appear after upgrading to V11

Hello,
We succussfully upgraded to V11 but have an issue with the logo on the left sidebar. Where normally the Dolibarr logo is (which can be replaced by your company logo), now there is nothing above the search bar. In the settings he have uploaded our logo (both normal as available in previous version and new square option) and that works fine. The thing is however that (even after emptying cache) the logo in the sidebar does not appear (and neither the standard Dolibarr one). The small square one in the top menu bar however is there.
Is this a bug in the new version? Or can anyone give me a tip how I can solve this issue? Our Dolibarr install is running on a hosted Linux server under PHP 7.2.
Many thanks in advance.