I briefly touched upon device properties (in my earlier post on device configuration and management) in the example of how to get the current device property profile. The "current property profile" of a device or source includes all the properties applicable to the device or source, including the standard properties (those that are defined by BizTalk RFID DSPI) as well as any additional custom properties of a specific device. Now, it may not be feasible for the provider or the device to persist the values of all of these properties, say for e.g. across a reboot of a device. To address such a scenario, BizTalk RFID provides support for a provider to specify the persistence status for a property (using the IsPersistent field in the device property metadata). Based on this information, BizTalk RFID automatically applies such properties every time after it establishes connection to a device. 

For e.g., you may notice something similar in your RfidServices.log file:

   6|   Info|091407 11:56:52|Going to auto-apply property profile for device ContosoTestDevice|[Device]
   6|   Info|091407 11:56:52|Property [CUSTOM:CUSTOMINTEDITABLEPROPERTY] was not persisted, adding to auto-apply list|[Device]
   6|   Info|091407 11:56:52|Property [CUSTOM:CUSTOMSTRINGEDITABLEPROPERTY] was not persisted, adding to auto-apply list|[Device]
   6|   Info|091407 11:56:52|Property [REBOOT GROUP:REBOOT] was not persisted, adding to auto-apply list|[Device]
   6|   Info|091407 11:56:52|Successfully auto applied 3 non-persisted properties|[Device]
   .....
   .....
   6|   Info|091407 11:56:52|Going to auto-apply property profile for source Antenna1 of device ContosoTestDevice|[Device]

Here's some background on how BizTalk RFID accomplishes this: every time there is a change in the value of one or more properties (for e.g. when you set a property or when you apply an entire property profile) BizTalk RFID creates a new version for the device in its version store to track the changes. After every successful connection to a device, it checks with the provider (using its device property metadata) if there are any properties that the provider is not persisting. If it finds such properties, it applies the values for these properties based on the latest values from its version store.  Note that the same thing applies for the source/antenna properties as well...

By default, this behavior is enabled and shouldn't be modified. If you really need to turn this behavior off, you can do that by setting RFID Manager -> Devices -> Connection Parameters -> "Auto-apply Non-Persistent Properties" to false.