So I've been farming minnows in an attempt to get the epic turtle mount, and the last 3 times I've killed the cavedweller not one single item has dropped. The 22 others I got over the last 3 days have dropped 5+ items minimum and I have no clue why this is beginning to happen

I made sure I tagged the mob first and did 90% of the damage, so if anyone has any ideas on how this can be avoided/changed please lmk.

Edit: What kind of drop rate are others getting? I was getting 2.7-3% for the first 16-17 minnows, but after that my drop rate dropped to 1.65%...