Hi Mike,
Please note that we cannot see the debug log level for sub-transactions, if there is any exception raised at highest level transaction level.
Check below snip for high level transaction log - At [Transaction_Call_0] is the sub transaction.
If there is no issue with high-level transaction execution, then the sub transaction will run and listed in the transaction manager with different ID, where we can check the log for same.
Regards,
Sai Vellanki.