What is causing meta descriptions to change on Joomla?

Hello. Is there someone who knows Joomla well?

I have a website and several pages switch their meta description page load. I know this since I see the difference between older cached version in Google versus recent version. I remember I added new descriptions to already existing description in sef404 extension/component and I believe there’s some kind of conflict. Joomla I am using is 1.5 and sef404 offers to update from 2.3.0.988 to 2.5.0.1040. Can there be potential risk of updating or disabling extension/component?

I have installed many Joomla! sites and, leaving aside the core of your question, I would recommend you to upgrade to 3.

Joomla! 3.3.1 is already released, and I can assure you that using 1.5 is discontinued and poses a very serious security risk to your site and even your users.

If you do not know how to do it safely, you have a good number of extensions to help you migrate:

Best regards.