It appears to be a recent repatriation from service OS.
They are stripped to access all areas for cleaning. This one seems to be stripped to the next level, I haven't seen any before with the dash removed.
Perhaps AQIS found, like me, noodle packets and plant material in an IIMV after its return and immediate disposal from Timor L'Este and decided to increase the level of cleaning required.
Someone here is very interested, so maybe best to declare to prevent a Blue-on-Blue over it
Cheers, Dave.