Custom filters on BelongsToMany throws BadMethodCallException

[dracon]

"message": "Call to undefined method Illuminate\\Database\\Eloquent\\Relations\\BelongsToMany::getQualifiedRelatedKeyName()", "exception": "BadMethodCallException", "file": "/var/www/bneapilocal/vendor/laravel/framework/src/Illuminate/Support/Traits/ForwardsCalls.php", "line": 50,

In EloquentBuilderTrait.php
In method joinRelatedModelIfExists
At line 299

Custom filters on BelongsToMany throws exception on the method call at line 299:
$relation->getQualifiedRelatedKeyName()
When I change it to:
$relation->getQualifiedRelatedPivotKeyName()

This works fine.