diff --git a/src/algo/algo.go b/src/algo/algo.go
index c1c07f3..3d5edb0 100644
--- a/src/algo/algo.go
+++ b/src/algo/algo.go
@@ -42,10 +42,8 @@ func FuzzyMatch(caseSensitive bool, runes *[]rune, pattern []rune) (int, int) {
 			// compiler as of now does not inline non-leaf functions.)
 			if char >= 'A' && char <= 'Z' {
 				char += 32
-				(*runes)[index] = char
 			} else if char > unicode.MaxASCII {
 				char = unicode.To(unicode.LowerCase, char)
-				(*runes)[index] = char
 			}
 		}
 		if char == pattern[pidx] {
@@ -63,6 +61,13 @@ func FuzzyMatch(caseSensitive bool, runes *[]rune, pattern []rune) (int, int) {
 		pidx--
 		for index := eidx - 1; index >= sidx; index-- {
 			char := (*runes)[index]
+			if !caseSensitive {
+				if char >= 'A' && char <= 'Z' {
+					char += 32
+				} else if char > unicode.MaxASCII {
+					char = unicode.To(unicode.LowerCase, char)
+				}
+			}
 			if char == pattern[pidx] {
 				if pidx--; pidx < 0 {
 					sidx = index
diff --git a/test/test_go.rb b/test/test_go.rb
index 3a9f1fd..4e255be 100644
--- a/test/test_go.rb
+++ b/test/test_go.rb
@@ -525,6 +525,16 @@ class TestGoFZF < TestBase
     File.unlink tempname
   end
 
+  def test_invalid_cache
+    tmux.send_keys "(echo d; echo D; echo x) | #{fzf '-q d'}", :Enter
+    tmux.until { |lines| lines[-2].include? '2/3' }
+    tmux.send_keys :BSpace
+    tmux.until { |lines| lines[-2].include? '3/3' }
+    tmux.send_keys :D
+    tmux.until { |lines| lines[-2].include? '1/3' }
+    tmux.send_keys :Enter
+  end
+
 private
   def writelines path, lines, timeout = 10
     File.open(path, 'w') do |f|