At page 55 for the draconic bloodline, there is the trait 'True Dragon', which grants Reptilia Bloodline 2. Usually, the Reptilia Bloodline X ability has an associated lineage mentioned. Like the above Draconic Bloodline, granting Reptilia Bloodline 3 - Draconic.
Since 'True Dragon' doesn't mention any lineage in specific, does that mean you can pick any 2 traits of any lineage you'd like, or is it still restricted to draconic?
The ability specifically says "having this trait unlocks additional bloodline traits within this lineage allowing a model to have X Bloodline Traits."
So it would mean that you have to remain within the Bloodline for your bonus traits.