You need two rings for caller ID to work in most places, except the UK, over analogue lines. How are you actually receiving the calls? (I don’t think you need the second ring, but you have to allow almost enough time for it.
How many rings are you actually getting, and how are you obtaining that figure? Ringback tone for the caller doesn’t correspond with actual rings and may start early.
What is “pause before answer” set to? There are reports of FreePBX actually answering too quickly, which suggests there are no deliberate delays, at least for VoIP: IVR answers with no ring