"uuid" was ref:ed in a continuation. Works 99.9% of the time because
the continuation is not actually delayed (and assuming we begin the
checks with non-truncated (system) cf:s it works).
But if we do delay continuation, the resulting cf map will be
borked.
Fixes #4187.
Message-Id: <20190204141831.3387-1-calle@scylladb.com>
(cherry picked from commit 9cadbaa96f)