patch 8.0.0066
Problem:    when calling an operator function when 'linebreak' is set, it is
            internally reset before calling the operator function.
Solution:   Restore 'linebreak' before calling op_function(). (Christian
            Brabandt)
diff --git a/src/normal.c b/src/normal.c
index f5e5475..5d0796f 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -1995,6 +1995,11 @@
 	    break;
 
 	case OP_FUNCTION:
+#ifdef FEAT_LINEBREAK
+	    /* Restore linebreak, so that when the user edits it looks as
+	     * before. */
+	    curwin->w_p_lbr = lbr_saved;
+#endif
 	    op_function(oap);		/* call 'operatorfunc' */
 	    break;