Inconsistent result when using `join`

[jackdeguest]

When using the join[1] query string parameter on endpoint /v1/module, such as https://fastapi.metacpan.org/v1/module/HTTP::Message?join=release&join=author, I am getting inconsistent result whereby sometime the property release will contain data and sometimes the same query will return this property release with a value of null

[1] (https://github.com/metacpan/metacpan-api/blob/7a3a16c3c1b7a9aea1b29adaa4bc9956eccd516d/lib/MetaCPAN/Server/Controller.pm#L131)[https://github.com/metacpan/metacpan-api/blob/7a3a16c3c1b7a9aea1b29adaa4bc9956eccd516d/lib/MetaCPAN/Server/Controller.pm#L131]