Guaranteed Delivery Issue

Hi All

I am getting the below error while trying to test one service:

Could not run ‘remote’. [ISC.0063.9143] [Tx] Duplicate transaction

There is two transaction with one tid. Is this the culprit, as I found the gd works fine with one transaction?

Can I conclude that there should be only one transaction between the gd start and gd end?

Have anybody faced any similar issue with GD?