Comment deleted...I forgot about the factory not being able to do items which return a multiple output (superconductors are made in pairs).

In the latest version of 2.1, this shouldn't be an issue

I am running 2.1.21. I was getting wonky results while trying to upgrade superconductors from common to rare by putting them in an RV loaded with qual mods, then reassembling, then putting them thru the RV again. I have that cycle going back and forth until all is rare. This method works great with everything else tried so far (mostly non-space-age-type items) but then I tried with SCs and I was not getting proper results. Then I tested by loading in an SC one at a time and observing the results. Sometimes I get a copper, or a plastic, or absolutely nothing. Sometimes they are upgraded and sometimes not but that part of the process is normal. But the loss of ingredients is not.

I get some loss of fluid too with items that need such (with the setting at "fluid as an item") but I figure that's because there is some faction stuff going on that involves round off the numbers and so this rounding sometimes results in fluid loss. But I guess that's a different effect altogether.

But the loss of ingredients is not.

The default return rate for items is 25%, same as the standard recycler, unless you change the setting. Even if you have set the return rate to 100%, if an item is crafted in pairs, then the return rate for recycling 1 of that item would be 50%

i.e. 1 iron + 1 gear = 2 yellow belt; then you recycle 1 yellow belt, you should get 1 iron 50% of the time and 1 gear 50% of the time; but it's random, if you recycle 4 yellow belt you could get 4 iron in a row and no gears, or you could get exactly 2 iron and 2 gears, or you could get nothing if you are really unlucky (this inherent randomness works the same way as the standard recycler)

Ah, that's the answer then.
I forgot to mention that my RV are set for 100%.
Ty for your quick replies.