1 Not drafting its desired contract and SLA requirements prior to opening the competitive process.
2 Basing its business case on invalid baselines.
3 Not developing a feasible BATNA (best alternative to a negotiated), so it has no well-thought-out alternative if a supplier radically changes its offer once at the negotiation table. This does happen.
4 Making itself vulnerable, perhaps by begin on a firm. Short deadline, thereby giving the supplier the leverage to act opportunistically.