ok My Sumenko Empress has 2 bloodlines: her fathers sons of raglabrok and her mothers architect. Shes married to a tengri clansman with blood of atilla. Its a matri marriage. I abducted some irishmen and I have 2 consorts with nine hostage bloodline. My son from tengri dude has 3 bllodlines as you would expect. My daughters father was a consort: she has NO bloodlines. None. Not her dads, not her mothers, not her grandmothers matri and not her granddads patri.
Can you upload your save? The mod I'm making should be able to fix this scenario however it comes about, but I can't reproduce the issue to test it with in my game.
I was also planning to make a replacement for the present debutante decision as part of another mod I'm making, but I might just make it separately.