I'm now of the opinion that this is a bug, I will raise a support ticket with support.

In this case, the issue may be caused by search filters narrowing the results too much. According to the Advanced Audit Trail documentation, searches are always executed within a specific Environment to search in (for example, Test, Acceptance, or Production) and a defined Time window. If the wrong environment is selected, or if the time window is too narrow or incorrect, the query can return no results, even when the Transaction ID itself is valid. Additionally, if the Limit value is set too low, relevant records may simply fall outside the returned result set.

To resolve this, make sure that the environment, time window, and limit settings exactly match what is used in the AAT UI when the data is visible there. Aligning these filters, especially the environment and time range. Usually, this resolves cases where queries return empty results unexpectedly.