Mention PR #8416 in CHANGELOG.md.

CHANGELOG.md

@@ -44,6 +44,9 @@
 - The TypeScript return types of the `getLastResult` and `getLastError` methods of `ObservableQuery` now correctly include the possibility of returning `undefined`. If you happen to be calling either of these methods directly, you may need to adjust how the calling code handles the methods' possibly-`undefined` results. <br/>
   [@benjamn](https://github.com/benjamn) in [#8394](https://github.com/apollographql/apollo-client/pull/8394)
 
+- Log non-fatal `invariant.error` message when fields are missing from result objects written into `InMemoryCache`, rather than throwing an exception. While this change relaxes an exception to be merely an error message, which is usually a backwards-compatible change, the error messages are logged in more cases now than the exception was previously thrown, and those new error messages may be worth investigating to discover potential problems in your application. The errors are not displayed for `@client`-only fields, so adding `@client` is one way to handle/hide the errors for local-only fields. Another general strategy is to use a more precise query to write specific subsets of data into the cache, rather than reusing a larger query that contains fields not present in the written `data`. <br/>
+  [@benjamn](https://github.com/benjamn) in [#8416](https://github.com/apollographql/apollo-client/pull/8416)
+
 ### Improvements
 
 - `InMemoryCache` now _guarantees_ that any two result objects returned by the cache (from `readQuery`, `readFragment`, etc.) will be referentially equal (`===`) if they are deeply equal. Previously, `===` equality was often achievable for results for the same query, on a best-effort basis. Now, equivalent result objects will be automatically shared among the result trees of completely different queries. This guarantee is important for taking full advantage of optimistic updates that correctly guess the final data, and for "pure" UI components that can skip re-rendering when their input data are unchanged. <br/>