This may be due to the Default Sub Ledger defined on the Security Profile of the user that posted the transactions.
You can review this as follows:
Ribbon style menu:
Select System
Select User Records
Locate the user that posted the transaction(s) and note the Security Profile they belong to as shown in the Profile column
Close the User Records window
Select Profiles
Scroll to find the user’s Security Profile
Click Global
The Default Sub Ledgers are listed at the bottom of the window
If these need amending, then click Edit, select the required Default Sub Ledger codes and then click Save.
Module Menus/Classic style menu:
From the main menu, select System Control
Select User Records
Locate the user that posted the transaction(s) and note the Security Profile they belong to as shown in the Profile column
Close the User Records window
Select Security Profiles
Scroll to find the user’s Security Profile
Click Global
The Default Sub Ledgers are listed at the bottom of the window
If these need amending, then click Edit, select the required Default Sub Ledger codes and then click Save.