3 tests are failing when updating rack to 2.1.4, but CVE patches are backported

--- a/Gemfile
+++ b/Gemfile
@@ -167,7 +167,7 @@
 gem 'diff_match_patch', '~> 0.1.0'
 
 # Application server
-gem 'rack', '~> 2.0', '>= 2.1.4'
+gem 'rack', '~> 2.1'
 # https://github.com/sharpstone/rack-timeout/blob/master/README.md#rails-apps-manually
 gem 'rack-timeout', '~> 0.5.1', require: 'rack/timeout/base'