Upgrading jails manually the first time

I migrated from iocage to plain jails some time ago. Now I'm upgrading to 11.1-RELEASE.

doas freebsd-update -b /usr/local/jails/mts2 -f /etc/freebsd-update-jail.conf --currently-running 11.0-RELEASE-p11 -r 11.1-RELEASE upgrade
freebsd-update-jail.conf is freebsd-update config with world component.

I receive the following errors during upgrade
abishai@vhost:~ % doas freebsd-update -b /usr/local/jails/mts2 -f /etc/freebsd-update-jail.conf --currently-running 11.0-RELEASE-p11 -r 11.1-RELEASE install                                
Installing updates...mtree: /usr/local/jails/mts2//boot/kernel: No such file or directory                                                                                                    
cd: /usr/local/jails/mts2//boot/kernel: No such file or directory
Jail seems to be upgraded, but is it OK to run jails without /boot ? I remember I didn't install it during jail creation. And, why freebsd-update tried to update it if it has only world component?
Jails don't have a kernel and run on the host's kernel. Therefor a jail doesn't require or need anything from /boot/.

As for freebsd-update(8) I do believe it runs an mtree(8) to create all the necessary directories. The /boot directory structure is defined in /etc/mtree/BSD.root.dist which always gets applied.