Addendum -- it is only 2.4.17-1 that has this problem. The Debian apache maintainers reverted the apache change that broke this (for now) in 2.4.17-2 -- see #803353. It looks like even apache is going to revert the change for the next 2.4 release -- https://bz.apache.org/bugzilla/show_bug.cgi?id=57785#c10