Recent editions (9.16.25, 9.17.22 onwards) of ARM have many empty grammar descriptions

Many empty grammar description sections are present in the ARM. Editions since 9.17.22 appear to be affected. An example is at https://downloads.isc.org/isc/bind9/9.18.0/doc/arm/html/reference.html#acl-statement-grammar.

The most recent edition which I have found where the corresponding section is not empty is at https://downloads.isc.org/isc/bind9/9.17.21/doc/arm/html/reference.html#acl-statement-grammar.

Some (apparently a minority) of the grammar description sections are present as expected, for example https://downloads.isc.org/isc/bind9/9.18.0/doc/arm/html/reference.html#view-statement-grammar.

Inspection of HTML source seems to confirm that the affected sections are indeed missing content, rather than that the content is hidden by some accident of styling.

It seems likely that there is a bug in the system used to generate the ARM.