Our Accounting system generates GUID named XML files, for example: 88546153-0493-46a6-88d7-2bbd83d436db.xml
Steps to reproduce:
1. Create a Flow:
Add a SharePoint trigger "When a file is created in a folder"
Send an email with Office 365 action "Send an email (V2)" by adding a attachment with File Name and File Content
Upload the 88546153-0493-46a6-88d7-2bbd83d436db.xml (file has content, file size 5k)
Flow fails with error: InvalidTemplate. Unable to process template language expressions in action 'Send_an_email_(V2)' inputs at line '1' and column '2571': 'The template language function 'base64' expects its parameter to be a string, an object or an array. The provided value is of type 'Null'. Please see https://aka.ms/logicexpressions#base64 for usage details.'.
If file is renamed to test.xml and uploaded again, the Flow succeeds and an email is received with the test.xml file attached to it.