At the moment, I have reverted to the last officially compatible version 1.46. But I will test the 1.56 version again. Thanks for the hint!
@feodor2 I moved to the most recent, final version of uBlock Origin which is 1.62 at the moment. The logger works fine in multi-process mode but in single-process mode, the logger popup window is very unstable. Some extensions, scripts and whatever else interfere considerably with the loading and display of the logger popup. It often remains empty. Resizing the logger window helps in some cases. I investigated this further and found that changing the advanced setting loggerPopupType from popup to normal may be a solution. In this case, the logger is opened in a normal window in which it loads fine as far as I could see until now. At least, on my computer with its current configuration. I'll keep an eye on that.
P.S.: @feodor2 Now, I have realised what you meant by using the context menu. I have never opened the logger interface via its icon context menu before. Indeed, this also works in both process modes to properly open the logger in a tab or window. However, changing the advanced setting loggerPopupType from popup to normal is of interest for those who prefer only one normal left-click on the logger icon as usual.