Bulk actioning on emails (>~200 selected)

When doing a bulk action on >200 emails approx, it comes up with a 400 error:

Failed to perform bulk action: Request failed with status code 400

The only way to do is a page at a time at the moment.

There is a corresponding logged error:

1. location: "body"

2. msg: "Invalid value"

3. path: "emailIds"

4. type: "field"

   With a bunch of email ids