Working Key: 1472_3_81445
Not Working Key: 1472_E2b_81445
Working Key: 1472_3_81445
Not Working Key: 1472_E2b_81445
They should work with non-numerical keys too. Can you doublecheck the comparison mode? Also, is the capital letter usage consistent between the two datasets? 1472_E2b_81445 won't match to 1472_e2b_81445.
Thank you Hans for your answer.
Sometimes it is easier than expected and it is advisable to keep doubting the data and not the process and the tool.
A small transposed number had crept in due to an error in the data of a matching table.