On the link (scroll down a little to the Bombs, M-4 parafrag link to page 250)
https://books.google.com/books?id=_m...day%22&f=false
On page 250 is says the M-4 clusters were used in France by fighter bombers but were found to be unsafe. The bombs worked loose, became armed, dropped prematurely and sometimes exploded during takeoffs or landings. They were replaced by M-81s and later by M-27s.