Da https://wiki.archlinux.org/title/Power_management/Suspend_and_hibernate: Hibernating to swap on zram is not supported, even when zram is configured with a backing device on permanent storage. logind will protect against trying to hibernate to a swap space on zram.
E mi sembra anche logico: zram è in memoria e con l’ibernazione il computer viene spento, quindi la memoria si resetta