current (7/2021) docker image does not build any more

During our tests building best practices using the daps2docker container we see that with image id 23796da72c68
we cant buld any more. We get the following error message (below). If we use an older image we do not get the build error and the results are looking good.

asciidoctor: WARNING: skipping reference to missing attribute: reg asciidoctor: WARNING: skipping reference to missing attribute: libo asciidoctor: WARNING: skipping reference to missing attribute: reg asciidoctor: WARNING: skipping reference to missing attribute: trade make: *** [/usr/share/daps/make/adoc2xml.mk:167: /daps_temp-NeVQATxDwa/source/build/.adoc/SLES4SAP-hana-sr-guide-CostOpt-12.xml] Error 1 ERROR: Converting the ASCIIDOC sources to XML caused a fatal error. Check the asciidoctor message above for details. (Exiting d2d_runner) DC-SLES4SAP-hana-sr-guide-CostOpt-12 has validation issues and cannot be built.

Start by reproducing the failure with image id 23796da72c68 and compare it with an older image that builds successfully. Read /usr/share/daps/make/adoc2xml.mk around line 167 and inspect the Asciidoctor warnings; done means the reported SLES4SAP document builds successfully without the fatal conversion error.