exactly the same here. 10/11psi primary, 14/15psi secondary/both. Stock exhaust, intake, HKS BOV.
I'd go with an intake leak, but it doesnt make sense that it starts at 14psi then drops. From my experience, intake leaks did the opposite, real slow to make boost. A similar thing happened when my secondary intake was leaking, dropped from 14psi to near nothing, but that happened at the usual changeover point (4500k rpm ish iirc), not as low as 2500 rpm.
Its almost like when it makes boost, it opens up a crack/split in some hosing, or forces something open with the pressure, causing it to drop.
IDK though.