IoWSG is not known for having annealing cracks, their cooling ovens were not subject to temperature fluctuations in the way older manufacturers' equipment was.
The crack also seems to be on the main body, not the base, where annealing cracks tend to appear, in my limited experience of them.
I'm slightly more familiar with annealing cracks on Monart, but I cannot tell from just a photograph whether or not a crack is from annealing or not.
However, my gut feeling is that is it a normal, ordinary, damage crack and nothing to do with annealing.
Does it ring when tapped with a fingernail, or thud?