We have used base64ToBinary() so as to avoid attachment corruption.
It was working fine till 17th of April 21, but suddenly now its throwing error and not able to create notes.
Error Message:
"error": {
"code": "0x80040278",
"message": "Invalid character in field 'documentbody': '\u001a', hexadecimal value 0x1A, is an invalid character.",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiExceptionSourceKey": "Plugin/Microsoft.Crm.ObjectModel.AnnotationService",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiStepKey": "753b8615-ecd8-db11-b397-0019b9204da9",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiDepthKey": "1",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiActivityIdKey": "a59d9bba-9b9b-48e2-a439-63fb63d3e1b1",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiPluginSolutionNameKey": "System",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiStepSolutionNameKey": "System",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiExceptionCategory": "ClientError",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiExceptionMesageName": "InvalidCharactersInField",
"@Microsoft.PowerApps.CDS.ErrorDetails.ApiExceptionHttpStatusCode": "400",
"@Microsoft.PowerApps.CDS.InnerError.Message": "Invalid character in field 'documentbody': '\u001a', hexadecimal value 0x1A, is an invalid character."
}
Flow in edit mode:

Any Leads why is this happening all of sudden? Were any updates pushed?
Process details of flow:
The flow triggers when there is a portal comment from dynamics portal. It fetches all the related attachment to portal comment & then creates a new note for the related case.