Reversible and irreversible discontinuities at around 573 and 823 K in the electric conductivity of a strained 175 nm thin film of ( La _0.8 Sr _0.2)_0.95 Ni _0.2 Fe _0.8 O _3-δ grown by pulsed laser deposition on SrTiO ₃ (110) are reflected by valence band changes as monitored in photoemission and oxygen K -edge x-ray absorption spectra (XAS). The irreversible jump at 823 K is attributed to depletion of doped electron holes concomitant with reduction of Fe ³⁺ toward Fe ²⁺ , as evidenced by oxygen and iron core level soft XAS, and possibly of a chemical origin, whereas the reversible jump at 573 K possibly originates from structural changes.