In SERVER-49336 we changed how client metadata is handled - it's set earlier in command processing, and the isMaster command implementations for mongos/d must not attempt to set it again. The original SERVER-49336 doesn't change the Embedded SDK's implementation of isMaster, but for some reason that hasn't caused a BF. When I backported SERVER-49336 to 4.4 and 4.2, we started seeing embedded_sdk_run_tests failures, "ClientMetadata was previously set".

I believe I should remove a call to ClientMetadata::setFromMetadata from the embedded isMaster, but I don't know why this has caused problems only on 4.4 and 4.2, but not on the master branch.