S2Member incompatible with Varnish cache?

My website is hosted by Dreamhost and uses s2Member pro to control membership. Dreamhost implements their own caching with Varnish. At some point I realized that caching is not actually working (I am not sure if it broke at some point, or if it never worked in the first place).

After doing my own troubleshooting, I contacted Dreamhost to figure out what the issue might be. Working together, we determined the problem is related to s2Member. In fact, I can reliably break caching by simply activating/deactivating the plugin.

Looking through the forum and other help files, I have been unable to find a fix or determine if this is a known issue. Any help would be appreciated. Please let me know if there is any other information I can provide that would be helpful.

Wordpress 6.2
s2Member Framework Version 230425
s2Member Pro Version 220421