Asymmetric routing issue: How to use PBR to make sure traffic that arrives on ISP-A leaves on ISP-A, not ISP-B

We have 2 ISPs (ISP-A and ISP-B).

On our edge router, ISP-B is configured as the default gateway while ISP-A has advertises 16,700 routes to us.

As a result, we occasionally experience traffic come in on ISP-A and leave via ISP-B and vice-versa(come in on ISP-B and leave on ISP-A). we have a script that sends an email anytime asymmetric routing occurs and from the looks of it, it happens ~4times a week.

I have basic knowledge of PBR, i know how to direct traffic based on the src IP using ACL, but i was wondering if pbr can also be used to fix this asymmetric issue.

my question is how do I use PBR to make sure that traffic coming in on ISP-A, leaves on the same ISP-A.

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thanks

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