A software developer and startup are negotiating about a mobile app. The startup wants to retain the intellectual property rights for the mobile app, but the software developer insights on retaining some rights. The startup expects the software developer to provide one year of free maintenance and support. However, the agency believes that $6$ months is more than reasonable. The startup wants several features and integrations, but the software developer believes some of them are unnecessary and will increase costs and development time. Over time, their discontentment grows with each other and they might reach an impasse by trying to "beat the other side." What terminology best describes this issue?

Bargaining zone

Self$-$serving reasoning in negotiations

Anchoring in negotiation

Escalation of conflict

Mythical fixed pie of negotiation