Included resource choosing wrong Arel table

I'm running into an issue where including one resource (user) ends up using another Arel table (account), and thus the include blows up with Internal Server Error: key not found: 11. 11 is the Account ID of the user, but the user ID is 68, which is specified on the parent resource as user_id.

I've stepped through the code a bit to determine that pluck_attrs in JSONAPI::Resource#preload_include_fragments has the wrong Arel::Table but I'm not sure what the cause of that is.

My models and resources are configured in a very straightforward manner:

JobApplication < ApplicationRecord
  belongs_to :user, inverse_of: :job_applications, touch: true, counter_cache: true
end

User < ApplicationRecord
  has_many :job_applications, inverse_of: :user, dependent: :destroy
end

Any idea why this would be happening?

JSONAPI::Resource#preload_include_fragments から始め、説明されている JobApplication/User の include 中に pluck_attrs がどのように Arel::Table を選択するかを調べます。レポートに記載された関連付け設定で問題を再現し、user を include すると Account ID 11 ではなく user_id 68 が使われ、キーが見つからないエラーが発生しなくなることを確認します。