I've run into a tricky issue with encoding backslashes in the projection_name where queries. In certain MySQL conditions, probably governed by https://dev.mysql.com/doc/refman/8.4/en/sql-mode.html#sqlmode_no_backslash_escapes, the projections don't get found because of the backslashes in the namespaced model names.

Storage seems to be fine, however in the queries the backslashes need to be doubled up (App\Models\Projections\MailStatsProjection needs to be transformed into App\\Models\\Projections\\MailStatsProjection). Within Laravel Eloquent there is a similar case with the MorphTo queries. Not sure yet how they have solved it.