https://qlever.dev/wikidata/EFrPQK returns no results
but https://qlever.dev/wikidata/Q4Tgkp returns 194.
This appears to be due to a very strict treatment of xsd:dateTime in QLever, where QLever requires all four of the required digits for the date. It might be worthwhile to relax this requirement.
This is query 214 in your WDQS query set.