Hello Titksha,
When you make any field recommended then SAP is no longer responsible for its validations.
Now,you have to perform validations on your own.As you said,for CLEAR pushbutton it is working as you want.Now,for other two button write validations on your own.
If you want fields to be mandatory for other two push buttons,then you have to write logic inside PAI for that button.To achieve this you can do as follows:-
When 'SAVE'.
If field1 is initial OR
field2 is initial OR
field2 is initial
Message 'Fill in all required fields' type 'S' display like 'E'.
Leave screen.
Endif.
<write your logic for save>......
Do similarly for other push buttons where you want as mandatory.
Regards,
Abdul