They're just not stoned enough over there. Offer them a canna butter brownie with walnuts, wait an hour, and then ask 'em. Probably be a whole different experience.. for all of you..
So you didn't put the washer fluid directly into the radiator, but rather into the reservoir, correct?
If that's the case, then there's been much less mixing between the two; some, but much less. The radiator fluids expand with the engine heating up, and the extra goes into the reservoir. When the engine cools down, it's supposed to suck it back into the engine. Expansion and contraction of a sealed or semi-sealed system.
If your reservoir has been changing levels (not from hot to cold, or vice versa, but hot-to-hot or cold-to-cold comparisons) then you (may/likely) have a breech some place.
The overflow hose/tube that leads from immediately below your radiator cap on most vehicles, over to the reservoir, can develop leaks. In that case, it may expel fluids under pressure, and suck air when trying to re-establish level on cooling.
Hopefully if you're loosing liquid, it's a minor issue. But in my experience, if your coolant is nearly a gallon low, there's at least some sort of 'trouble in River City.'
The nice part of anti-freeze is that it has an indistinguishable odor. And you can locate a leak with a black light some times. (*Plus the added joy of playing with black lights!!

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******!!!!!! If you -do- have a leak, sufficient to cause any pooling/puddles near your vehicle, make sure to keep any pets (yours or others) away from it. If you're using traditional ethylene glycol for coolant (as opposed to the purportedly safer more environmentally sound newer blends), it can shut down their kidneys and lead quickly to death. And it's sweet both to smell and taste.!!!!*****