Yes the wire that goes to the switch does form a loop. Confusingly, often the wire that’s “supposed” to be the neutral or white wire is, in this configuration used as a “hot” or black wire. If you look closely at the picture, the white wire running between the light and the switch has little black sections at either end. This is supposed to be representing the idea that, in this case, the white wire is being used as black. Glad it’s working now.

https://www.buildmyowncabin.com/electrical/wiring-switch-power-into-light.html

At a guess, you may have this situation. Power comes into the light junction box and then runs down and back to the switch before going into the light. If you connect it all together in the light junction box, you could be bypassing the switch.

Is the offending light on the same switch as the other four? If not, are any other lights on the same switch as the offending one? It sounds like the light was wired to bypass the switch and just get constant power from the breaker/panel. Does your husband recall how he wired the offending light? Pictures of the junction box wires would help.

Whirlpool with a true sparker. Broiler burner at the top starts no problem. Eventually I got the problematic sparker working by fiddling with the sparker. Literally bending the housing a bit to alter the gap distance.

The cooktop burners work fine. It’s the burner inside the oven itself that won’t ignite. Oven fills with gas and the sparker sounds like it’s working but no flame or heat