Last chunk throws Non-256KiB chunk size multiple error

I have a direct creator upload implementation which mostly works, however the last chunk always returns an error. The file itself is uploaded, and I can view it in the cloudflare dashboard. The error means I my js won’t recognize the upload onSuccess so I can’t progress to the net step in my code. I’ve got my chunk size set to 50mb, and it fails with files smaller and larger than this value.

Is there something I need to do, or is this a bug?

My console log shows: Error: tus: unexpected response while uploading chunk, originated from request (method: PATCH, url: {url}, response code: 400, response text: {
“result”: null,
“success”: false,
“errors”: [
“code”: 10031,
“message”: “Non-256KiB chunk size multiple”
“messages”: null
, request id: n/a)