Translation:The tribble bit the targ that lay on the table.
An -'e' on the yIH would be OK, but I don't think it would clarify anything. yIH is clearly the subject of chop. The object is the whole phrase raSDaq Qotbogh targh and I could see how that can be a complicated noun phrase, so I imagine you might think an -'e' could help in there. When a -bogh phrase has 2 nouns, -'e' can help clarify which is the one you are focusing on. However, there's actually only one noun in that phrase, so an -'e' won't really help clarify anything there either. I don't think an -'e' in this sentence would help clarify, unfortunately. I think you just need to get used to -bogh phrases acting as a noun.
Agreed, an -'e' would not help anything.
The tricky part of this sentence is trying to decide whether raSDaq is attached to Qotbogh or chop. Does the tribble bite a targ-on-a-table (raSDaq Qotbogh targh) chop yIH or does the tribble on the table bite a targ raSDaq, (Qotbogh targh) chop yIH.