I.e. if they can only manufacture 1000 widgets, but 10,000 people want to buy one at the given price point, the gained market share is still only 1000 individuals. The number of people who want one but can't get one due to lack of supply is not market share.
Temporary under-pricing might be a valid strategy if AMD is planning to ramp up manufacturing capacity, but comments further down in this thread suggest they lack the fabs to do that.
The only way they'd set the impression of overpricing is if they actually overpriced. They did the opposite.
Whether it was a mistake in pricing or some calculated second-order strategy, we'll never know. What we do know is they're leaving cash on the table whether intentionally or not.
Temporarily (keyword) underpricing to hurt competitors is not unheard of but I don't see how it will hurt intel unless it significantly shifts mindshare for the next ~2 years and allows AMD to get a real foothold in the server market.
I am not sure it is a bad choice.