Personally I use a "refundable" account as an asset.
2025-07-01 Train Company
assets:creditcard -50 EUR
assets:refundable:employer
2025-08-01 Employer
assets:checking 2050 EUR
assets:refundable:employer -50 EUR
income:salary
2025-08-01 Credit Card Company
liabilities:creditcard = 0 EUR
assets:checking
As the refund is already tracked in the salary transaction, there is no need to track it again on the payment of the CC.