What problem does this address?

The Query Loop block uses the iAPI client-side navigation feature when the "force page reload" advanced setting is disabled. However, the Post Content block is not currently supported inside the Query block when the client-side navigation is in use. This measure was taken to prevent issues with potential incompatible blocks within the Post Content, as there was no way to detect them inside the WordPress editor.

What is your proposed solution?

Blocks need to declare client-side navigation compatibility explicitly, and the logic that enables/disables client-side navigation automatically is already in place. We just have to declare the Post Content block as compatible.