( ! ) Fatal error: Can't use method return value in write context in \themes\wplms_modern\templates\directory\course\index.php on line 24
We are not able to replicate the error on our test and demo sites .
However there are some styling issues with default directory layout in modern theme .
We are on fixing this soon and modern child theme will be updated soon .
I had to change the code for the title image in templates\directory\course\index.php to proceed...
Btw, I do not fully comprehend why are you using such a complex title image selection code in each page php, as for some of them there is no even way to set up a different image.
For pages like author, archive, etc, your code picks avatar image from the first post on the page...
Yes we are able to replicate the issue with the archive pages .
Will be fixed in the update of wplms modern theme.