No change from triggers

Is that normal ?

I made triggers for some table to change value in same record by condition.

If on form for this table i make change value of some field (if this value is changed then trigger start) and press SAVE then trigger run and make needed change in record (change value of other fields of this record)

But if i make change in record and press next button (to move to next record in qbe) and system ask me - save change ? - and i press YES trigger run(i see my print() ), but now trigger did not make any change in record.