JCB tries to check if the text is already translated, but this is not easy... here is the code that does this:
So as you can see it checks if the string and the uppercase of the string is the same, but the safeString option converts all numbers to words... and for this use case it will change 3 to THREE, and that is why it fails to detect the correct behavior.
I can fix this... so please open this issue on gitHub, and we can add the fix in the next update, I will on gitHub give you the code string you should change in the mean while to get this to work.