Sourcetree not finding installed bundler

[Martin Sommer]

I am doing Ruby development with Git, and have bundler (default: 2.7.2) installed.

When I do a Commit in Sourcetree, I receive the error `/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/rubygems.rb:283:in `find_spec_for_exe': Could not find 'bundler' (2.7.2) required by ...`.

If I do the same `git commit` from the MacOS console, it works.

Why would Sourcetree not be able to see my installed `bundler`?