diff --git a/src/uu/expr/src/syntax_tree.rs b/src/uu/expr/src/syntax_tree.rs
index e660b096d..3570dd6a4 100644
--- a/src/uu/expr/src/syntax_tree.rs
+++ b/src/uu/expr/src/syntax_tree.rs
@@ -295,8 +295,9 @@ where
         if pattern_chars_clone.peek().is_none() {
             return Err(ExprError::UnmatchedOpeningBrace);
         }
-
-        quantifier.push(curr);
+        if prev != '\0' {
+            quantifier.push(prev);
+        }
         prev = curr;
     }