When a test,  called via "test as step" from another test, is moved to another project location using Cut/Paste, there is a warning that the Parent test will be broken, but still if confirmed by user it will break the Parent test execution when trying to find the Child one.
Using drag and drop option with mouse works fine and does not break the parent/child relation.

Workaround is to re-create the Test As Step in Parent test that calls the Child test.