The third-party provider of content creation in Claromentis, CK Editor, has rescinded free use of the built-in spell checker.

As a result, the spell checker will no longer appear in content creation areas of the Intranet (News, KB, Blog, text component) in newer site versions:

8.12.19 or 8.13.5+

There are other free third-party tools for end-users to implement and fulfil this purpose instead e.g. Grammarly, Wordtune etc and these can be controlled in browser to match your preferences.