I also experienced this on a deployment when using focal machines. The workaround I applied was to set net.ipv4.conf.all.rp_filter = 1 using the sysconfig's charm sysctl config option.
I also experienced this on a deployment when using focal machines. The workaround I applied was to set net.ipv4. conf.all. rp_filter = 1 using the sysconfig's charm sysctl config option.