"once users engage with this particular feature, they become less likely to purchase"

"this is clearly users' favorite feature."

Your description is a bit vague, but here is what I am thinking. I am wondering if these folks were not going to buy anyway, but they stop to "engage" this feature because it has gee-whiz appeal. So basically you are presenting non buyers with a toy and since they are not busy with the task of buying anyway, they play with the toy.

Be careful. Correlation does not (always) imply causation.