I selected Matching Text in the Documents Bookmarks window. Scrivener immediately crashed. (Should I have selected some text first?)
Nitram
Scrivener 3.1.5 on Mac OS 10.13.16
The Matching Text function will take the text from the current document, all of it, and then search for that text in other documents. It is quite a processor intensive job and may take some time, but shouldn’t crash. Did it actually crash or did you get the spinning ball?