Please remove all the code for serializing/deserializing values, all these are performed by HivePress if you added a field via the model filter hook. I realized there’s an easier way to do this, there’s the attributes API which allows you to add a new attribute (listing field with stored values) and also add it on back-end via a single hook. Please check some samples here Search · user:hivepress attributes · GitHub If you have any extension with a Repeater field you can var_dump attributes via this hook to check how this repeater field is defined.
Hope this helps.