"When he was jealous, she made fun of him."
Translation:Kiam li estis ĵaluza, ŝi mokis lin.
https://en.wikipedia.org/wiki/Esperanto_grammar#Tense "Estis" is the main verb and is set in the past, so shouldn't "mokis" be in relation to when that main verb occured and therefore be "mokas" since it happened at the same time as when he was jealous? Otherwise it would mean that in the past, when he was jealous, she had made fun of him already.
You don't really have a subordinate here (both sentences can stand alone - "He was jealous" / "She made fun of him); they follow each other logically, but they don't necessarily depend on each other.
It would be slightly different if you said "She made fun of him when he was jealous" (there's a closer cause-effect at work here), but in any case "esti" is the subordinate verb here, not "moki".
You are both wrong. That "relativity" only applies to indirect speech. In other words, the verbs keep the same forms they would have in direct speech.
Ili diris "Ni iros" -> Ili diris ke ili iros.
If it's not indirect speech, only put a present tense for something that is in the present. The position of the "kiam" subphrase doesn't change anything.