Ore scrubber not removing 500,000 germs as specified

When slime (or I suspect anything with germs) is picked up, 5% of the germs are transferred to the duplicant who picks it up.  In this case, Nikola had 39,438 germs, and the slime had 1,649,503 germs:

Then, just after Nikola picked up the slime, roughly 5% transferred to her, and were removed from the slime:

It takes Nikola a few seconds to get to the ore scrubber and as you can see, some germs have died off:

So far so good.  But, when Nicola uses the ore scrubber, which is supposed to remove 500,000 germs, you can see that almost 20,000 germs are added back to the slime (or simply not removed).  Nicola's count has only decreased slightly, and is in line with the rate it was decreasing naturally, so they didn't come from her.  Only about 800 germs are in the surrounding Oxygen and they were dying off, so that doesn't seem to be the source either.

The same thing happens at the next ore scrubber.  Nearly 20,000 reappear again:

And, you guessed it, on the third ore scrubber, nearly 20,000 more germs reappear:

I could understand this behavior if the germ count on slime increased over time, but it doesn't, it actually decreases quite rapidly (13% death rate per cycle for being overpopulated plus another 13% death rate per cycle for being in an Oxygen environment).

Obviously, 60,000 germs isn't that big of a deal in the grand scheme of things, but this was only 185 Kg of slime.  I often have duplicants moving a lot more than that at a time, and a couple hundred thousand errant germs can make the difference between a germ-free base and a slimelung outbreak.

And speaking of ore scrubbers.  It seems kind of silly that they would only remove 500,000 germs in the first place.  Why not just remove all germs but increase the time the duplicant must sit there spinning the drum and the amount of Chlorine used?  This seems like a far more reasonable solution than lining up 10 ore scrubbers to make sure a big load gets cleaned completely.

Thanks,

Misca