The date of death of Hans Adler has been set by the Dutch Ministry of Justice as September 30, 1942.
However, according to the Sterbebücher of Auschwitz, the camp registration that has been partially preserved, Hans Adler died there on August 24, 1942.
For the time being, the website joodsmonument.nl shows the official dates of death, as published in the Nederlands Staatcourant by the Ministry of Justice at the time.
Sources: Auschwitz prisoners / Museum / Auschwitz-Birkenau ; Nederlandse Staatcourant dd 17 mei 1950.