Steps to reproduce:
1. Download the Flex in a Week projects archive (FiaW_Day4_ProjectArchive.zip). Sorry, I cannot locate the download link any more.
2. Extract and run project ex4_05_solution. You should see a list of employees.
3. Click on the evaluation note of Athena Parker (9) until the numeric stepper appears.
4. Select the value 9 in the edit field and replace it by value 55 for example.
5. Hit TAB to leave the field.
The value reverts to 9.
The value commits as 55.
Workaround (if any):
Needs messing with focus events, I guess.
Note: The same steps but leaving the field with a click somewhere else or with <enter> commits the new value as expected.