They say:
"Our crawler reports pages that have duplicate meta descriptions only if they are exact matches.
"A tag is a short summary of a webpage's content that helps search engines understand what the page is about and can be shown to users in search results.
Duplicate meta descriptions on different pages mean a lost opportunity to use more relevant keywords. Also, duplicate meta descriptions make it difficult for search engines and users to differentiate between different webpages. It is better to have no meta description at all than to have a duplicate one.
HOW TO FIX IT
"Provide a unique, relevant meta description for each of your webpages.
For information on how to create effective meta descriptions, please see this Google article.
You can also view the On-Page SEO Basics: Meta Descriptions article"
Recommended by Semrush (looking at FreeREG)
They say: "Our crawler reports pages that have duplicate meta descriptions only if they are exact matches.
"A tag is a short summary of a webpage's content that helps search engines understand what the page is about and can be shown to users in search results. Duplicate meta descriptions on different pages mean a lost opportunity to use more relevant keywords. Also, duplicate meta descriptions make it difficult for search engines and users to differentiate between different webpages. It is better to have no meta description at all than to have a duplicate one. HOW TO FIX IT
"Provide a unique, relevant meta description for each of your webpages. For information on how to create effective meta descriptions, please see this Google article. You can also view the On-Page SEO Basics: Meta Descriptions article"
Pages with duplicates: "Search Query | FreeREG https://www.freereg.org.uk/" "About | FreeREG https://www.freereg.org.uk/cms/about" "Accessibility statement | FreeREG https://www.freereg.org.uk/cms/about/accessibility-statement" "Cookie Policy | FreeREG https://www.freereg.org.uk/cms/about/cookie-policy" "Your reviews | FreeREG https://www.freereg.org.uk/cms/about/your-reviews" "Help | FreeREG https://www.freereg.org.uk/cms/help" "Frequently Asked Questions (researchers) | FreeREG https://www.freereg.org.uk/cms/help/frequently-asked-questions-researchers" "Opportunities to Volunteer with FreeREG | FreeREG https://www.freereg.org.uk/cms/opportunities-to-volunteer-with-freereg" "Member Login | FreeREG https://www.freereg.org.uk/cms/refinery/login" "Member Login | FreeREG https://www.freereg.org.uk/cms/refinery/users/login" "FreeREG | UK Parish Register Records https://www.freereg.org.uk/cms/refinery/users/password/new" "Terms and Conditions | FreeREG https://www.freereg.org.uk/cms/terms-and-conditions" "Contact Us | FreeREG https://www.freereg.org.uk/contacts/new" "Forename abbreviations | FreeREG https://www.freereg.org.uk/emendation_rules" "Transcription County Selection | FreeREG https://www.freereg.org.uk/freereg_contents/new" "Transcription County Selection | FreeREG https://www.freereg.org.uk/freereg_contents/new?locale=en" "Search Query | FreeREG https://www.freereg.org.uk/search_queries/new?locale=en"