SageMaker Studio Data Wrangler: "An unexpected error has occurred."

When I get to the "Data Types" part of creating a flow in SageMaker Data Wrangler, it says, "An unexpected error has occurred. Try again. If the problem persists, contact AWS support."

I have contacted support via the "Get Help" button within the Data Wrangler screen, but have not received a reply.

I can see all of my features on the right hand side, and I can see the visualization of the first 2000 rows, but if I change the data type (i.e. from string to long) it doesn't save those changes. The "Preview" and "Save" buttons at the bottom right, below all of my features, are not clickable, and I can't add a Step to the flow after "Data Types," because the "Add Step" button is also not clickable.

I added a Data Quality & Insights Report before the "Data Options" to see if it could read my file or detect any problems. It was able to read the file, and correctly identified all of my feature types:

The "Feature Types" are all "string" in the "Data Types" dialog, but the Data Quality & Insights Report correctly identifies them as datetime, text, long, etc.

I have saved, closed and re-opened the flow. I have started with several new flows in case one loaded weird or wrong. I have shut down Sagemaker Studio and restarted it. I have tried in Chrome and then Safari / cleared cookies. I have tried several .csv files. I have created a second SageMaker domain and tried it in there. I have tried 3 days in a row, in case there was some temporary outage or glitch.

I can train a model with the same csv, and it works. But I'd like to do some pre-processing in Data Wrangler, and I can't due to this error.

I'm out of ideas on how to fix this, and unfortunately the error message isn't informative enough for me to diagnose it further.

Thank you.