For each email message you view received from a sender, Gmail determines type of encoding used by the sender and then displays the message. If Gmail is unable to accurately detect the encoding of message, then it can’t display the message properly, the message will appear garbled. Google email service team is currently working on this issue meanwhile you can still view garbled messages in Gmail.
1.If Garbled messages shown by Gmail, then open original message.
2..Click down arrow next to ‘Reply’ and click Message text garbled?
Garbled message will be shown clearly in readable text format by Gmail.