Well, yes and no 
I did an upgrade (which worked fine), but later I rebuilt the whole openHAB machine (I’m running openHAB on a Proxmox LXC environment). I built this new machine from scratch, as I had another issue (unrelated).
As I’m still using text configuration, I simply built the new machine, then copied all files from old machine-openHAB-conf to new machine, but no json configuration was copied
My dimmers never did fail, so it’s very unlikely that the update introduced an issue here.