Be grateful, blessed, if no varroa there ... YET
Clarify for us please. Are you seeing this tossed brood every couple of weeks, regularly ... or, are you seeing tossed brood after each inspection.
If noticed only after inspections, then the next question is what are you doing with brood frames during the inspections? For example, taking out of the hive and putting down out of the hive, in the sun or in the shade, etc. Could the problem be your method?
22 degrees mentioned, I am assuming celsius. That is definitely not too cold to affect brood. At times I inspect a 5 degrees. If the brood is put in the sun, it is entirely possible it is being cooked not chilled.
If noticed each couple weeks, inspections or not, then you have a brood disease or pest that needs to be diagnosed.