Fred

It might related to your hosting enviroment, but without exactly seeing your configuration it is hard to say. Start with cleaning up your warmup table following this guide: https://swteplugins.com/docs/warmup-table/

Then set Prebuild Speed on unlimited and don`t enable Limit Simultaneous Threads.
Also disable generate Critical CSS as it should speed up prebuild as well.

Did you enable Caching for logged in users in Swift? When you disable it, does it make any difference?

It might there is another cache layer active? Looking at the response header it might related to Litespeed cache.

If you need help, start with sharing your site URL

Thanks for clarification. It is weird and I can’t reproduce it on our end. But, as I said it is not impossible.

However, Swift will always make a copy of your existing .htaccess. (.htaccess_swift_backup) in case something goes wrong, so you can always easily revert.

Thanks for reporting.

Please share the URL of your site. Also, are there any errors in browser console?
If you disable Merge Styles, does that solve your issue?

To avoid misunderstanding, support for Swift Lite is limited and configuration is not included.

In general, GTmetrix does full load, so including all the scripts that are running in the background. As long as it loads after the content, it doesn’t matter.You need to check the waterfall in GTMetrics or test with Pingdom, as they check ‘realistic’ page speeds. The same speeds that a visitor would experience (with some delay depending on the test location).

Only with Pro version you are able to use lazyload scripts feature, with which included scripts will be loaded very last, and won’t delay rendering process.

Enabling or disabling plugins can have catastrophic affects on your site. It can cause issues with plugins and can render your site inaccessible. In our documentation we have a general warning, but it might a good idea to add this also in Swift Plugin Organizer itself. Thanks for letting us know.