Brass flows back into the ejector hole. Normal load right. Working up to Hot load on left, with expanded primer pocket. Primer fell out. Caused by high pressure. The primer pocket may open with 1 loading that is very hot. Or it may take several reloads at maximum to slowly expand the web area of the primer pockets. Common to Rem, Sako, Savage ejectors. If the primer flows back into the firing pin hole, around the pin, pressure may be to high or the hole is oversize.