Steps to reproduce the issue

Open up Menu item of type Compact list of tagged items. Click the tab Metadata and fill in the Meta Description field. Click the button Save or Save and Close!

Expected result

The Meta Description should be visible in source code!
If I open up the Tag that Compact list of tagged item is linked to, and click the Publishing tab and fill in the Meta Description and click the button Save or Save and Close, I get the following result in page source:
which is normal:

Actual result

The Meta Description text is saved but not showing in page source -

System information (as much as possible)

Setting Value

PHP Built On Linux server.olympic.rs 2.6.32-431.3.1.el6.x86_64 #1 SMP Fri Jan 3 21:39:27 UTC 2014 x86_64
Database Version 5.5.46
Database Collation latin1_swedish_ci
PHP Version 5.4.45
Web Server Apache
WebServer to PHP Interface apache2handler
Joomla! Version Joomla! 3.4.8 Stable [ Ember ] 24-December-2015 19:30 GMT
Joomla! Platform Version Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
User Agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:43.0) Gecko/20100101 Firefox/43.0

Additional comments

As I mentioned the solution would be to fill in the Tag Meta Description field (Components - Tags) instead of Compact list of tagged menu item's Meta Description field