No attribution window
The single most common failure. Without a stated period, every past introduction remains a live claim, and the vendor is left arguing about a conversation from last year with no principled basis for saying no.
No submission standard
If a list of company names counts as a referral, partners will send lists of company names. A minimum standard, meaning a named contact with a described need, submitted through an agreed route, protects the partner from wasted effort as much as it protects the vendor.
Optimising the rate instead of the fit
Referral volume is driven by whether the partner's own customers routinely raise the problem you solve, and by whether the partner is reminded when they do. A higher rate paid to partners whose customers never have the problem produces nothing except a more expensive nothing.
Manual fee calculation
Fees reconstructed by hand each month produce disputes, delays, and eventually partners who stop bothering. The fix is unglamorous: put the partner and the referral date on the opportunity record.
Treating a referral as a qualified opportunity
Most referral partners do not do discovery and should not be expected to. The introduction is warm access, not a late-stage deal, and a sales team that treats it as the latter will report that referral quality is poor.