Describe the bug

I recently started using managed identity authentication functionality from SqlClient after using our own access token caching implementation, but I'm seeing a lot of random token refreshes and I'm wondering if this is expected. Below is a screenshot from app insights showing the refresh calls over a period of 24 hours of one app instance.

Before:

After:

I would expect the token to be cached around 24 hours before a refresh is triggered if the token lifetime is 24 hours. What I am experiencing though is that it refreshes at a seemingly random interval.

This behavior is slowing down a bunch of our requests as you can probably imagine.

One other thing I noticed is calls to the below endpoints when the token is refreshed. We did not see these pop up before the change.

• GET crl3.digicert.com/Omniroot2025.crl
• GET mscrl.microsoft.com/pki/mscorp/crl/Microsoft%20RSA%20TLS%20CA%2001.crl

Currently I'm considering moving back to our own implementation, because this is just plain dumb behavior.

To reproduce

Just run a application with using the below segment in the connection string.

Authentication=Active Directory Managed Identity

Expected behavior

Refresh the token just before the token expires (5 minutes before or something).

Further technical details

Microsoft.Data.SqlClient version: 4.0.1
.NET target: 6.0.1
SQL Server version: Azure SQL Server
Operating system: aspnet:6.0-bullseye-slim