I cannot see a problem.
Please provide FULL and EXACT information, property settings, event handler code, setup code, steps ...
It's all me. The most important:
Thanks for reporting the issue was resolved.
We don't understand a bit. The Precission property must be greater than 0. Otherwise, an "error" will not occur. The "Formating" event, and consequently the OnChange event, does not occur.
I retested this with 3 default TAdvEdit controls on the form and the code:
I sent a primitive form to try it on.