Issues with search form widget

I am using search form widget for a custom post type and it has some weird issues. When I am typing a search in the search form it shows fine, but when I delete one letter for example the search query changes to previous word and the new word(without one letter), and if I re-add the letter it switch again and usually there are no results. To reproduce just type on search form, then delete a letter, re-add the deleted letter you won’t get the same results.