"Unknown" transactions on ItemMovementReport

I have a report from one of our data guys that he's seen this in a couple of instances. No clue where the Type=11 comes from but the behavior is same as what you're describing. Unfortunately we can tie it back to at least 2.0.0127 and prior so your suspicion of a recent update being the cause may not be the case.

Hello Mike,

Thank you for your question.

I have found that "unkown" item movements can be caused if a Worksheet 260 is used on an item that already exists at the store. If this worksheet is processed again for the same item at the store, it will automatically update the quantities at the store equal to the quantities in HQ. To prevent this from happening, please be sure that worksheet 260 is only used for sending new items down to your stores.

If you need to update an item’s attributes, use a worksheet 250 while in maintenance mode.  

You need to download the new report from CustomerSource; https://mbs.microsoft.com/customersource/support/downloads/reportslibrary/rms/ModifiedReports/modifiedreports_rmsstoreoperationsreports.htm

Report - Item Movement History with InventoryTransferLog.Type 11 Added
The Item Movement History Report has been modified to accurately display results for records that have a value of "11" in the InventoryTransferLog table in the Type field. The InventoryTranferLog.Type of "11" signifies a quantity adjustment that was made as a result of processing a Style 260: Download Items worksheet. This new InventoryTransferLog.Type of "11" was added as part of the Microsoft Dynamics RMS Hotfix 1 (build 2.0.0106). (April 23rd, 2009)