Hello

LeonidS suggested that remove the _see_more language key from the Polyglot which I did but it didn't help so I added it back to the Polyglot. What else can I do to fix this so I can limit the number of characters to a timeline post. See More doesn't seem to be working.

Could you please provide a direct link to a page where the problem can be seen.
'See More' should be automatically added to posts with a lot of content. If you are saying that you have a default (non-modified) version then it should work.