I think that when they came up with the bait some of them were thinking of an additive bonus, but it got implemented as a multiplicative bonus.
So (pulling numbers out of my arse, I don't know the real numbers)
While they think, and most people were expecting, a 0.5% chance increased to 3.5% by a bait bonus of 3%
the actual bonus is 1.03 x 0.5%, resulting in a 0.515% chance.
After all, these were the same devs (not even, really, the current ones, but the ones from a decade ago) that thought that humans had a flat 40% of colored ore, and that the 20% Elf bonus would make it 60%, when in actuality every resource square has its OWN percentage of colored ore, independent of race, and that the elf 20% bonus was multiplying that, so that if a human was 30% colored for a specific spot, the elf would be 36% colored, etc. I don't think any of the current devs were in their current positions when ML, KR and HS were in development.