Unsaturated ketone coupling pattern
You are close. The triplet part is the coupling of the enantiotopic hydrogens at C4. The width of the C5 blowup is ~20 Hz in width which means J = ~7 Hz. The smaller coupling is due to allylic coupling with the methyls (C7 and C8). Assuming J5,7 and J5,8 are the same, then the six hydrogens produce a septet. You just can't see the outer peaks because they are too small. If coupling to the two methyls is different then the septet will appear broadened because of lack of resolution. A larger blowup of C5 would reveal the outer peaks (one and seven).