What’s happening is that due to an issue with the way we’ve got the DB configured, we’re unable to properly handle certain types of emoji - when a lead is received that contains data like this, it’s truncated and persisted, which means that when we try to retrieve it, we get errors like the ones you’re seeing. We have a fix in place for regular form submissions (i.e. via pages) but it turns out that leads created via the API take a different code path.
I’m hoping to get a fix deployed soon (hopefully tomorrow). I don’t know what your setup is, but if you have control over the code that’s invoking the API, you could try sanitizing the lead data before it’s sent to our API. If you have your own record of the lead in your system, I can get you a couple pieced of information that you might be able to use to correlate.
As of right now, you have 2 leads that are in this state. What you can expect to see if that, in addition to that API call failing, things like CSV export will likely be broken for you too.