Amazon listing for Quantum Break changes date to May 4th?

Lock if not OK, but Amazon UK have changed the date on their website.. weird considering we have a hard date:For reference

With the fact they've said development has been tough might they be delaying it by a month? It could be a good decision if it happens.
If it needs more time, that's fine and I wouldn't mind, honestly. I'll be plenty busy with U4 multiplayer and Dirt Rally throughout April and a May release would mean I'd get to enjoy QB without school getting in the way.
I think they had the right date originally, as I read someone say they got an email about it changing. Either that, or maybe it was previously undated.
I got an email but it just says

"We're awaiting a revised estimate from our supplier, and will email you as soon as we receive this information."