Wondering what could cause multiple intake valves to not seal properly on a low hour Diesel

If it's like some diesels they don't put a seat into head, they just grind valve into casting and that to me is not a great idea, a buddy just realized this on a 6.4 Ford with international diesel, I could be wrong but sonething to look at...

possible burnt valve

What kind of diesel?

Detroit 12.7

Yes more info what kind, application, and you said low hours, does that mean low factory hours or low hours after someone has been in it? How do you they are leaking?

I have rebuilt a few of older Detroits mostly the two stroke Detroits 16v, 12v, 8v, and 6v

If it is in a newer truck with emissions and has a egr system that is not properly working the egr issue could gum up the intake causing the valves not to seal. Just one possibility, really need more info.

Is this running now what is it in? Bad valve springs/broken out of adjustment?

Sounds like 14 Apache needs to fabricate you up some piston cooling jets.