I tried above steps i.e. removed Chair 2 from asset.json
Then it gave error - frappe.exceptions.ValidationError: Row #1: Asset Chair 1 is already Fully Depreciated
So i went ahead and removed Chair 1 also
Then it gave error - frappe.exceptions.ValidationError: Row #1: Asset ERPNext is already Fully Depreciated
So it appears, problem is not with items itself but with some other data
Following might be imp lines from error trace
fixed_asset.py", line 45, in make_asset_purchase_entry
purchase_invoice.py", line 72, in validate self.validate_fixed_asset()
accounts_controller.py", line 618, in validate_fixed_asset