Update read-related-data.md (#19919)

Author: Rick-Anderson

aspnetcore/data/ef-rp/read-related-data.md

@@ -48,7 +48,7 @@ There are several ways that EF Core can load related data into the navigation pr
 
   ![Explicit loading example](read-related-data/_static/explicit-loading.png)
 
-* [Lazy loading](/ef/core/querying/related-data#lazy-loading). [Lazy loading was added to EF Core in version 2.1](/ef/core/querying/related-data#lazy-loading). When the entity is first read, related data isn't retrieved. The first time a navigation property is accessed, the data required for that navigation property is automatically retrieved. A query is sent to the database each time a navigation property is accessed for the first time.
+* [Lazy loading](/ef/core/querying/related-data#lazy-loading). When the entity is first read, related data isn't retrieved. The first time a navigation property is accessed, the data required for that navigation property is automatically retrieved. A query is sent to the database each time a navigation property is accessed for the first time. Lazy loading can hurt performance, for example when developers use N+1 patterns, loading a parent and enumerating through children.
 
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