To the surprise of absolutely no-one.
Force majeure will be discussed at length here. Material shortage and price inflation provision in the contract in 2019 could not possibly have foreseen the effects of Covid and the Ukraine war on actual prices and material availability.
That's before we get to the bit where the idea that a company that has never built an entire warship before would be able to do so for an average £250M was somehow deemed credible. I'd expect that Babcock may be discovering that a shiny new shed does not a shipyard make. They'll get there, but this dispute resolution is just trying constrain the losses they're looking at. I suspect there may be some contract / cashflow stage payments as well that are at risk given the most recent pics of HMS Venturer.
This is not a disaster by any means. Just a reality reset.