Severe DNS leak in Firefox Desktop 151.0 Beta 1 with DoH "Max Protection" enabled

In Firefox Desktop 151.0 Beta 1, I'm experiencing a severe DNS leak even with DNS-over-HTTPS (DoH) set to "Max Protection". I've tried all available troubleshooting steps (including resetting `network.trr.*` preferences, disabling extensions, and testing in a clean profile), but the issue persists. > The same configuration works correctly in the previous version (150.x). Has anyone else encountered this regression?