I sometimes create very short custom clozes consisting of only one or two words, mainly prepositions. Sometimes the result is very strange, with the cloze embedded in another word. I think this happens when the selected characters happen to appear somewhere else in the sentence, nearer the beginning.
One example might explain the issue: I entered “Io non sono interessato {{a}} una relazione seria.” The result: “Io non sono interess{{a}}to a una relazione seria.”
I create them from existing clozes, using another word or expression. In the example above, I think used "Io non sono interessato a una {{relazione}} seria.” as the starting point.