Datamart shows fake successfully refresh

Hi experts,

I need your help!

I have a Master_Datamart which appends data from 2 other datamarts (say datamart1, datamart2). Each of the datamarts has a field called MaxValue (same name in both the datamarts)

1. I made  changes in transformations (PowerQuery) to MaxValue of datamart2 and saved (reloaded).
2. I created a test report on datamart2, and I can see the result of the change made to MaxValue in the datamart2.
3. I reloaded Master_Datamart (open from transformation, saved) data, but the changes made in datamart2 are not showing in Master_Datamart.
4. I tried to remove datamart2 in the Master_Datamart append step, reloaded Master_Datamart loaded data, re-added again, I still don’t see the changes I made on MaxValue datamart2 when I create a test report on the Master_Datamart, but the changes are visible on the datamart2.

I don’t see a refresh error in Master_Datamart. When I check the refresh history, I see a complete successful refresh status with the correct data/time of the refresh. But I know that a correct refresh did not happen. I don't see the changes.

Does anyone know what is wrong and how to fix it?

Thanks in advance for your help.