I am pointing out the inconsistency of your rules, nothing else. If this is punishing any of the people who submitted, then I'm sorry, but they should have read the rules and followed them in the first place.
You only are accepting longer captions now because somebody pointed out your mistake, why didn't you do this in the first place? The rules are still as follow;
No images/emotes or anything, I'm going to list all the captions in pure text form for easier judging.
You didn't even bother to change it "halfway through" when, as you said, you started accepting these. Rules on such things are supposed to be well-thought, solid, and remain unchanged since day 1, not to leave disadvantages to anybody who created their entry before rules were changed. Clarify a rule is one thing, but saying that you removed one while it still remains there is a completely different thing.