Vertex AI was unable to import data into dataset

[m_e_]

1. On the Datasets page, I create a new dataset (text classification -- multi-label).
2. I choose "Upload import files from your computer", selecting my training data *.csv file (263 MB).
3. Then, I wait a while: maybe 30 minutes to an hour.
4. Half the time, I get an email like this:

"Vertex AI was unable to import data into dataset "[dataset]"

Hello Vertex AI Customer,

Due to an error, Vertex AI was unable to import data into dataset "[dataset]".

Additional Details: Operation State: Failed with errors

Resource Name: [resource]

Error Messages: Internal error occurred. Please retry in a few minutes. If you still experience errors, contact Vertex AI.

To view the error on Cloud Console, go back to your dataset using [link]

Sincerely, The Google Cloud AI Team

Following the link takes me back to the dataset import page, where it says "Unable to import data due to errors". If I click "Details" it has the same error message as the email. It won't allow me to browse the dataset or train a new model, because it failed to import.

What puzzles me is that sometimes it imports successfully or partially, sometimes it doesn't, with nearly identical datasets on the very same day, leading me to believe the file size, CSV formatting, and character encoding must be acceptable. Even so, I have tried:

• Ensuring that the CSV formatting is correct, with quotes and escapes where necessary.
• Scrubbing all characters outside the ASCII printable range (32-126) and trimming input.

I don't know what the problem is because the error message does not say anything meaningful. Any help is appreciated.