I just wanted to follow up that I disabled the workaround for this in https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/383f036c58fb0405fc25d89ff7ecf44a54c9afc9 and on Debian the armhf and armel builds pass and autopkgtest / ci.debian.net pass, so that validates that this issue in lxcfs indeed is fixed.