As per the notice requesting you to check through setup wizard and sage export options posted on our news page,

Please ensure you check the option in SAGE > CONFIGURE SAGE EXPORT OPTIONS... THIS IS VERY IMPORTANT !

There is a setting in place to over-ride standard invoices to goto a single account, this went out in the release set to enabled

Goto ADMIN
Sage Export
Configure Sage Export Options
Advanced Options
Set the option to NO or Yes as desired
If Yes, set an account number which exists in sage

If you have run the export, dont worry you can re-run the export after changing the options by doing the following

Goto DRIVE C:
GA_EXports
Delete the folder for the corresponding date
Go back to Sage Export in GA2
Click 'View Previous Export Date'
Choose the correct date and click 'repeat this export'