We’re still working through a few residual issues with encoding. For example, some entities may be improperly escaped in strings appearing in profile bios. In plain english, you’ll see stuff like “&” still on your profile page. But the problem should be resolved with updates.
Also, some users may be seeing increased frequency of duplicate updates from those they follow. Previously, we would attempt to catch duplicate updates and prevent them from being published. This appears not to be working and is tripping up folks and some of the automated tools that publish to Twitter. We’re working through that.