L2ARC failing to rebuild after reboot

Could any moderators confirm what is different/special in the "Proxmox" ZFS versions?
PVE ships with recent (we try to be quite close to upstream and package new versions once they get tagged by the openzfs project) versions of ZFS
the kernel part is shipped with the pve-kernel packages the userspace part with zfsutils-linux, zfs-zed, zfs-initramfsk, and a few library packages,docs, ...

We do not have too many patches on top of the upstream code (mostly for integration into PVE/Debian, sometimes if there is a patch that fixes an issue we've seen we pull that in, before a release gets tagged)

I hope this helps!