Depreciation reserves unplanned depreciation when the depreciate flag switched off

To enable an impairment to be applied to a fully reserved asset negative unplanned depreciation has been applied to asset after switching off depreciation.   The asset is then impaired to the same value as negative unplanned depreciation.  Depreciation and create accounting are then run in final mode .   The depreciation flag switch off has been ignored and depreciation has been added to the asset.  Can anyone advise how we can prevent depreciation being added to the asset.