Google search console error regarding "name"

For our detail page based on JEM Simplelist page Google search console stated an error: Critical problem - Field "name" is missing. 

That is related to structured data. The field is missing in the event markup. This is considered critical because without it, Google cannot display the event properly in search results.

The event page has several tags "itemprop" for startdate, url to provide the structured data but the name is missing at top level (although it is at the venue-id1 level)

Is that an issue of my installation? my settings? 

Installation: Newest joomla 5.4, jem 4.3.4 and php 8.4, using JEM Simpelist for the details page. 
 

Hello hklages,
JEM 4.3.4 actuallz does have valid microdata in the simple list and also on the event detail pages.
You may be using template overrides where the microdata is not fully implemented. If you are using template overrides, please disable them for testing with the Google Rich Data Checker: search.google.com/test/rich-results
If the error persists, please let us know so we can take a closer look.

Edith: you can also use the schema validator validator.schema.org/