It's not uncommon for Dynamics GP users and partners to "tweak" GP by adding SQL triggers or custom stored procedures. As with any modification to the standard GP behavior, it can have unanticipated consequences, especially when there are integrations to other components present.
Here's a script that lists all the triggers present in the selected database. Note that GP comes with its own triggers, so it can be tricky to determine what was added/modified versus what was part of the original installation. This script shows both the table's created date and the trigger's created date in order to help sort out the mystery.