diff --git a/src/regexp_bt.c b/src/regexp_bt.c
index 4082f59..793faaf 100644
--- a/src/regexp_bt.c
+++ b/src/regexp_bt.c
@@ -3360,8 +3360,17 @@
 		int	mark = OPERAND(scan)[0];
 		int	cmp = OPERAND(scan)[1];
 		pos_T	*pos;
+		size_t	col = REG_MULTI ? rex.input - rex.line : 0;
 
 		pos = getmark_buf(rex.reg_buf, mark, FALSE);
+
+		// Line may have been freed, get it again.
+		if (REG_MULTI)
+		{
+		    rex.line = reg_getline(rex.lnum);
+		    rex.input = rex.line + col;
+		}
+
 		if (pos == NULL		     // mark doesn't exist
 			|| pos->lnum <= 0)   // mark isn't set in reg_buf
 		{