[Darryl Ramm]

Key info would be IO Buffer size and clocking and are you using aggregate IO?

If recording live with no artist monitoring through Pro Tools get the IO buffersize as large as possible.

Especially sure you are not using Aggregate IO... it’s easy to end up with this selected by mistake as the playback engine and then have clicking issues with that. I would delete the aggreagate IO device to avoid this.

Is there any external digital audio or clocking source? Doubt that is the issue here.