Index: src/ex_cmds.c
===================================================================
--- src/ex_cmds.c	(revision 57777)
+++ src/ex_cmds.c	(working copy)
@@ -5044,6 +5044,8 @@
 			prev_matchcol = (colnr_T)STRLEN(sub_firstline)
 							      - prev_matchcol;
 
+			if (Unix2003_compat)
+			    beginline(BL_WHITE | BL_FIX);
 			if (u_savesub(lnum) != OK)
 			    break;
 			ml_replace(lnum, new_start, TRUE);