This paper reports the first observation of the Jacobi shape transition in ³¹P using high energy γ rays from the decay of giant dipole resonance (GDR) as a probe. The measured GDR spectrum in the decay of ³¹P shows a distinct lowenergy component around 10MeV, which is a clear signature of Coriolis splitting in a highly deformed rotating nucleus. Interestingly, a self-conjugate α-cluster nucleus ²⁸Si, populated at similar initial excitation energy and angular momentum, exhibits a vastly different GDR lineshape. Even though the angular momentum of the compound nucleus ²⁸Si is higher than the critical angular momentum required for the Jacobi shape transition, the GDR lineshape is akin to a prolate deformed nucleus. Considering the present results for ²⁸Si and similar observation recently reported in ³²S, it is proposed that the nuclear orbiting phenomenon exhibited by α-cluster nuclei hinders the Jacobi shape transition. The present experimental results suggest a possibility to investigate the nuclear orbiting phenomenon using high energy γ rays as a probe.