Interesting.. I'll take a look

Edit:

It seems like the PQRT in that save specifically (and presumably other pretty old saves) has some different attributes, because when I copy those PQRT particles, they have the same behaviour, and newly placed PQRT does not.

Edit Mk. 2:

All of the PQRT particles from Benassi's save have a tmp2 value of 65533, whereas in normal PQRT this should be between 0 and 5. The tmp2 controls which of quartz's colours the particle is, so when it is 65533, the value '1048448' is added to each RGB component of the colour, making it completely white, and of course when the find mode code tries to dim it, it has very little effect. This is why the particles are white even in find mode... not too concise really.