Relevant Products: Exclaimer Cloud - Signatures for G Suite
When sending a message with Client-side and Server-side enabled, the received message has two signatures. One next to your message and one at the end of the reply chain.
This is caused by the 'Insert this signature before quoted text in replies and remove the “–” line that precedes it' option being unchecked within Gmail for the user. Without this option checked, the client-side signature will be inserted at the bottom of the email chain and Exclaimer Cloud will not detect it so will add server-side signature as well.
Checking this option to enable this feature will resolve the issue.