thanks for the support.
I think I stressed your theme design a little bit.
I defined my header by custom css with height 0 and got various problems.
I now noticed that by increasing header height above 0 the breadcrumbs also worked fine in chrome.
To minimize my problems, I now decided to adjust my theme design to a narrow header line instead of a right sidebar.
Therefore this issue is no longer relevant for myself.
Thanks and best regards