Posts via Postie have an extra ‘standard’ format applied

It’s most odd. Our blog is set to display excerpts. This works fine. But a post that comes in from Postie seems to do something odd, it adds a new ‘Standard’ format to the end of the list of formats and selects this, the post then ignores the excerpt rule/setting and displays in full and we have to manually edit the post and select the correct ‘Standard’ format for that post to then display correctly.

This is what we see just for posts from Postie:

• This topic was modified 6 years, 5 months ago by timmorris.

The page I need help with: [log in to see the link]