joomla: Changes that I make to template_css.css are not showing up on site

Question

PROBLEM: I make changes to template_css.css, but those changes do not show up on website.

1 - I have tested the website on multiple browsers.

2 - I have cleared the browser cache on all of them.

3 - I have turned off Administrator/SEO-Settings/Search-Engine-Friendly-URLs

4 - I do not see an .htaccess file in the site's directory

5 - I can download the css file to my computer (via ftp), but cannot upload to that directory ... 755 permissions ... the site is on my webhost account that I have been using for many years.

6 - I am able to change&save the template_css.css (via *Administrator/Template Manager/Customize Template/Stylesheets/edit css/template_css.css*), and then download the css to my computer (via ftp) and verify that the change did succeed.

7 - I can navigate to the css file directly (via my browser), and it shows the OLD values.

8 - I can arbitrarily change the name of the template_css.css (via my ftp client), and the Administrator/Template Manager/Customize Template/Stylesheets/ will reflect the changed name.

9 - I can examine the html via firebug, and the css for the element in question indicates the correct css file: www.my_site.com/templates/pinboard_av_j17/css/template_css.css ... but it shows the OLD values.

10 - I can rename the .css file (via my ftp client), and then navigate to the old filename (via browser (with cleared cache)), and it will still show the .css file (with the old values).

The site is: b4x.si

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EDIT: this morning I repeated #7 (navigated directly to the css file) and noticed that the css file has been updated so apparently at some point many hours after making the changes in the template manager, the css finally updated.

However, please keep in mind that initially after making the changes, if I ftp'd the css file to my computer that I Could see the changes (#6), but if I navigated directly to the css file via browser that I could Not see the changes (#7).

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