I posted to your FAQ, but it didn't display on the page, so I thought I repost it again with what I've tested. I have the same issue as the above users.
Using wordpress 3.2.1
Using a FRESH install of WP To Twitter 2.3.8 (previously was using an upgrade from 2.3.3 to 2.3.8 but wanted to test the fresh install to see if it works)
Publishing via wp-admin
Host provider is Dreamhost
Custom tweets sometimes do not get published. Only the default ones that you set in your settings do. It's been very hard to reproduce. Everything was working perfectly fine in 2.3.3.
I do notice that character count is incorrect when you save/publish a post that has twitter text in it. To reproduce:
1) Edit or Add a new page
2) Type some text into the twitter box
3) Click "Save Page" or "Publish"
4) View the character count. It says 0. If you place your cursor in the box and type something, the character count shows the correct number.
5) Repeat steps 1 through 3 to see it reset back to 0.
^^ I don't know if that's the reason why custom tweets are NOT getting published out, but I thought that was a little strange.