Very unusual, I didn't know that there were hemiparasitic plants producing green leaves in the broomrape family, so thank you for teaching me something new. today.
It looks lovely, I see that has been found a few times even here in Norway, probably accidentally imported with lumber etc. In some places it's placed on the 'Black list' , in other places it's described as a potentially attractive garden plant with low risk of spreading to the woods where we already have other Melampyrum species, a couple of them are very common, but they haven't got the conspicuous blue colour.