0.4.5: Killing dumplings does not increase the mana % count

I killed a dumpling in Lister’s realm and the bestiary count mana % did not increase from 21% -> 22%.

I was personally curious about this as I thought it didn’t go up after killing sometimes, but I was wondering if it gave less than 1% and just rounded the display to the nearest 1%.
Would probably be kind of ridiculous to have to kill over 100 to summon 1, though, so I always just hoped it was my imagination.