Is transaction_id of paypal Mass Payout Item mutable?

I use https://developer.paypal.com/docs/api/payments.payouts-batch/v1/#payouts-item_get api to request my pay开发者_高级运维outs through Paypal.

My question is: when a payout item changes its status from i.e. SUCCESS to REFUNDED, does transaction_id change as well (i.e. to the ID of a refund transaction)?

It is not clear from the API docs; the only thing clear is that transaction_id could be empty in some cases. They also call it "The" transaction_id, so it kind of hints it's immutable after it is set, although it's only an assumption.