Smallish model (7b) require a somewhat simplified grammar tho. Especially with longer complex instruction I found more luck by joining all the conditions with ands and to have everything that's a follow up and need to happen in order joined by then, instead of having more natural sentences.
So instead of "write a short story of a person that's satisfied at work" something along the line of "write a short story and the protagonist must be a person and the protagonist must be happy at work" boost comprension especially as the condition list becomes longer.