Hi,
From looking at the log, I’m not sure how the update would have stopped this working as you expect; in fact I would expect wait for network to have to be enabled for it work as you’ve described. I’m not saying what you are describing is impossible or wrong, just odd that’s all.
Anyway you may have mileage with simplifying the fstab entry, for example intr has been deprecated since kernel 2.6.25. I would try something like:
media.home.lan:/tmp/mnt/sda1 /home/osmc/mnt/mybook nfs noauto,x-systemd.automount
Also I would consider looking at autofs, as it more tolerable of network outage; or in this case just not up yet. Details can be found here:
Thanks Tom.