"Sir! The zombie is trying to eat me!"
Translation:qaH! muSop 'e' nID yInbogh lom!
It doesn't say that. I once thought that too, but reread the section carefully. It says "The past tense of the translation (I saw...) comes from the verb in the first sentence, qIppu' he/she hit him/her (-pu' perfective). In complex sentences of this type, the second verb never takes an aspect suffix..."
This doesn't mean the aspect suffix moves from the second verb to the first. It's just explaining why it was translated into English as past tense: qIppu' means something was hit and the hitting was completed. In English we use past tense to say that: hit instead of hits. yaS qIppu' he/she HIT him/her. Well, if he HIT (past tense) her, then I SAW (past tense) that. It's all about the English translation, not how you handle the Klingon grammar.
So the rule is that you simply can't put a type 7 suffix on the second verb of a sentence-as-object, not that the suffix moves to the first verb.