What could be the reason for the recurring AP and AR document to be released.

Can you check if the preferences is enabled?

@MichelleW, the recurring process never releases anything on its own. Generate Recurring Transactions (AR504000 and AP504000) only creates the documents, as Balanced or On Hold. Something else releases them afterward, and the usual culprit is an automation schedule on the release screens rather than on the recurring ones.

Open Release AR Documents (AR501000) and Release AP Documents (AP501000) and click the clock icon on the toolbar. History lists the scheduled runs, and the Total Records link opens the documents each run processed. If your recurring invoice and bill numbers are in there, that's your answer. View opens the schedule itself. In the screenshot, View and History are greyed out because that screen has no schedule.

If nobody needs the schedule, clear its Active check box and save. It's reversible.

If it's there on purpose for other documents, AR and AP work differently. For AR, select Hold Documents on Entry on AR Preferences (AR101000). Recurring invoices then generate On Hold, and the release screen only picks up Balanced documents. That setting puts every new AR document on hold, not just the recurring ones. For AP, that setting doesn't reach recurring bills. They copy the template's Balanced status unless AP approvals are on, so narrow the schedule instead with a row on its Conditions tab that leaves those vendors out.

One note on Sales Orders Preferences: Automatically Release IN Documents releases the inventory documents created from shipments and sales order invoices. It doesn't touch AR invoices or AP bills, so I'd leave it as it is.

If neither release screen has a schedule, check Customization Projects (SM204505) for anything published that touches recurring documents.