different behavior of several (hopefully) equal installed jails

Hi,

I am running halve a dozen jails on one freebsd host The jails were created and are managed with iocage. Both the host system and the jails were installed with a version from the FreeBSD 13 line and upgraded and updated since then. Actually they all run FreeBSD 14.3p12.

Since a longer time (I can not remember either the exact point of time or the exact FreeBSD version and the patch level) I notice the folloing described behavior:
* I run "pkg update && pkg upgrade && pkg autoremove && pkg clean" across all jails
* for some packages which are installed in more than one jail the packages is not updated in all jails
* if I run the pkg-cmd-line again after some days the package will be updated in some more jails (somethimes in all affected jails)

Is that a expectable behavior? If not - what can I do to determine the reason for the observed behavior?

Best regards
    Ulf