patch 7.4.732
Problem:    The cursor line is not always updated for the "O" command.
Solution:   Reset the VALID_CROW flag. (Christian Brabandt)
diff --git a/src/normal.c b/src/normal.c
index c29ab1a..0ec8037 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -8493,6 +8493,9 @@
 	    /* When '#' is in 'cpoptions' ignore the count. */
 	    if (vim_strchr(p_cpo, CPO_HASH) != NULL)
 		cap->count1 = 1;
+	    if (curwin->w_p_cul)
+		/* force redraw of cursorline */
+		curwin->w_valid &= ~VALID_CROW;
 	    invoke_edit(cap, FALSE, cap->cmdchar, TRUE);
 	}
     }