Zoho CRM API v2 Access Token refresh limits

Zoho CRM API v2 Access Token refresh limits

I know a single Access Token is valid for 1 hour. And a Refresh Token can be used unlimited times to generate Access Tokens (although only the most recent 30 Access Tokens remain valid). But are there any time-based restrictions on how often you can use a Refresh Token in a given time period, say per minute?
If I repeatedly use a Refresh Token in a short amount of time I eventually get an "Access Denied" response. However, after waiting a few minutes I can re-use that same Refresh Token again without issue.