what affects blight spore drop rates?

hello, my favorite mechanic is blight. i mainly play SSF but i was hoping to find a way to farm a sporeguard.

there is not a lot of information about how sporeguard drops but from videos i was able to gather it seems to drop from the loot explosion at the end. I want to do some testing myself, but since i am SSF my resources are limited, so i was wondering if anyone else knows.

do any of the following factors affect the quantity of items dropped from the blight loot explosion?

1. pack size (i wonder if immune response atlas gives me a larger loot explosion, based off more mobs during the encounter)
2. number of blight lanes
3. number of bosses in blight encounter
4. modifiers with "additional rewards" from the atlas.


i was also curious, if sporeguard could drop from map blight encounters loot explosion? or if it was exclusively blight/blight-ravaged maps.


Thanks!