diff --git a/src/ast/rewriter/seq_rewriter.cpp b/src/ast/rewriter/seq_rewriter.cpp
index abf5809cb..ac0261f61 100644
--- a/src/ast/rewriter/seq_rewriter.cpp
+++ b/src/ast/rewriter/seq_rewriter.cpp
@@ -3337,11 +3337,11 @@ expr_ref seq_rewriter::mk_regex_union_normalize(expr* r1, expr* r2) {
     else if (re().is_dot_plus(r2) && re().get_info(r1).min_length > 0)
         result = r2;
     // (R1 \ R2) U (R2 \ R1) = R1 xor R2
-    else if (re().is_intersection(r1, a1, a2) && re().is_intersection(r2, b1, b2) && 
+    else if (false && re().is_intersection(r1, a1, a2) && re().is_intersection(r2, b1, b2) && 
         is_complement(a1, b2) && is_complement(a2, b1)) {
         result = re().mk_xor(a1, re().mk_complement(a2));
     }   
-    else if (re().is_intersection(r1, a1, a2) && re().is_intersection(r2, b1, b2) && 
+    else if (false && re().is_intersection(r1, a1, a2) && re().is_intersection(r2, b1, b2) && 
         is_complement(a1, b1) && is_complement(a2, b2)) {
         result = re().mk_xor(a1, re().mk_complement(a2));
     }