Arabic terms are normalised before they are matched: hamza forms are folded together, alef maqsura and yaa are treated as one, and taa marbuta matches haa. You can type a term the way you write it and still find a record catalogued the other way.
When normalisation changed your query, the results page says so. It is stated rather than silent, because a search that quietly searched for something else is worse than one that found nothing.