Custom search with "SQL OR" does not paranthesize the where clause properly ..

Seems like when we have a where clause with an OR in it, we dont add paranthesis in the right place, thus we get

group_id IN (1) AND custom_3 = 12 OR custom_4 = 15

instead of

group_id IN (1) AND ( custom_3 = 12 OR custom_4 = 15 )