This has just happened to me, the only thing I think I may have differently is had the fence finished before the tilling was done. Cant be certain haven’t been so prepared with fencing before, but kind of sure I normally only think about fencing fields when I get my crop is being eaten warning.
Just wanted to add just in case it might help with replicating the bug.
Just to add, in 0.8.0, I’ve fenced fields before and after the fields themselves were ready for planting, and regularly Till at least 1 year in 3, but have never had this happen.
On the other hand, I almost never start by Tilling (prefer to plant Clover the first year), so have not precisely replicated the set of circumstances you describe. I’ve got a new game just started, will see if I can duplicate the problem’s circumstances.