AWS Network Load Balancing

Hi,
I converted a test site to use network load balancing and I am seeing intermittent security messaging stating:

SSL received a record that exceeded the maximum permissible length. Error code: SSL_ERROR_RX_RECORD_TOO_LONG

And it happens more often when doing a hard-refresh of the site.

When the site is not using the network load balancer it does not have this issue.

This is Windows Server 2016 w/IIS.

Any help would be appreciated.