The most common cause of this is the use of Corrections to add project and costing details to a purchase ledger invoice transaction while it is still in the ledger batch (before it is posted to the ledgers).
This causes the system to add a detail line into costing, and then the system adds a second one when the transaction is actually posted to the ledgers.
Our developers have confirmed that this is an issue in Dimensions 2.51j and that this will be resolved in a future version of the software. In the meantime, we do not recommend using Corrections to add costing details to any transaction until the transaction has been fully posted.
You can correct the project and cost centre values by entering a negative value miscellaneous transaction for the additional value against the project and cost centre using the following process:
Navigate to Costing, Miscellaneous (Ribbon menu) or Costing, Transactions, Miscellaneous (classic/ module menu).
You can set the Batch option via the Options button on the entry screen if needed
Change the drop down to Active Transaction(s)
Enter relevant transaction details, ensuring that you use the same project and cost centre codes, and that the value of the transactions is entered as an opposite value of the original transactions (if the original line is positive, enter a negative value and vice versa)
Once completed, Save the transaction
You can then either check the transaction from the batch (if batched), or if the batch option is not set, the transaction will be posted.
This will reverse out the additional value and only affect the project and cost centre figures.