Joomla 5.3.1 (and maybe after) was been shipped with an incompatible version of .css with the shipped .js in media/vendor/bootstrap. The vendor/bootstrap works on most browsers, but there are issues with old Mac desktops.

For the next minor release please ship with an updated bootstrap.css (BS 5.2.3 works fine).

Also - please do not strip out the BS version comments in your shipped version of BS. It makes it hard to check what version of BS you are shipping - and has probably lead to this problem?

You'll need to use a Joomla template that uses media/vendor/bootstrap (and not current online versions of bootstrap).

You'll find the BS grid system will break on old macs, resulting with the (default) XS layout only. It looks bad on large desktop screens.

Steps to reproduce the issue

When using a template that uses vendor/bootstrap.min.css - and a script from vendor/bootstrap/js (say dropdown.min.js) - you will find on macOS Catalina Safari 13, BS grids will break and it will not render properly.

Expected result

For large screens, content should be shown in grids.

Actual result

Only shows layout for XS for any screen size. (No grid functionality)

Also other issues...

System information (as much as possible)

Bug shows up on old Mac - use lambdatest - macOS Cataline Safari 13, Joomla 5.3.1

Additional comments

To fix, overwrite media/vendor/bootstrap/css/bootstrap.css (bootstrap.min.css and bootstrap.min.css.gz) with new versions. (BS 5.2.3 works fine)
The existing vendor/bootstrap/js seem to work (but might need more testing).