I cannot reproduce this issue with any combination of server configuration parameters. I suspect that there's a third party plugin which causes this issue by outputting information to the browser before Akeeba Backup can initialise itself. Please try deactivating your other plugins one by one until you find out which one causes the issue. Then contact its developers and ask them to check their code for any whitespace and unprintable characters before the opening PHP tag, newlines or other whitespace after the last ending PHP tag in their files and any ini_set and error_reporting calls which raise the error reporting level beyond E_ERROR and/or cause output of PHP warnings to the browser.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
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