These are some sutta’s in which kamma is listed as a possible cause for unfortunate things one could experience. Those sutta’s clearly suggest Buddha’s view was not: “‘Everything this individual experiences—pleasurable, painful, or neutral—is because of past deeds.’
https://suttacentral.net/sn36.21/en/sujato
https://suttacentral.net/an5.104/en/sujato
https://suttacentral.net/an10.60/en/sujato
Maybe from these lists of possible causes stems the idea to introduce other causes, nyiama’s, and to see kamma as a seperate cause for illnesses, affliction etc. and to introduce other causes like medical causes (bile, phlegm etc) or causes related to climate, and other extern causes.
Often people wonder if some unfortunate event is due to kamma. I know some sangha make use of the nyiama’s. They use them in such a way that if one can find medical causes, external causes or causes related to climate, one can drop the idea it is due to past bad deeds.
For this is find no support in the sutta’s.
Siebe