Odd leakdown test results...

[Hammerhead]

A cold test causing a leak may be the sign if an injector pintle & seat starting to leak, however at warm temps it seals up.
Not sure what your mechanical aptitude, but I believe it was Aussie ISX (?) Had a thread about dismantling 871 injectors & using toothpaste to lap them in and reseal them.
If this is in your wheelhouse and you'd like to try it, I have tools (yes the injector dis&assembly tool) and would very much be interested in experimenting with you...