Can't launch application when using Bundler 2.7.2

[gbp]

At mySociety we host 10 Alaveteli installs. All expect for CZ can be deploy using the master/develop branches.

For CZ the application won't start (via passenger) and we need to patch Gemfile.lock to use the previous version of Bundler.

diff --git a/Gemfile.lock b/Gemfile.lock
index 2974f8dc0..b1a1fa8f8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -773,4 +773,4 @@ DEPENDENCIES
   zip_tricks (~> 5.6.0)

 BUNDLED WITH
-   2.7.2
+   2.7.1

Need to look into the root cause of this. Maybe bumping to Ruby/Bundler 4 might resolve this.