A PXE enabled Distribution Point will generate a number of files under C:\ProgramData\Microsoft\Crypto\RSA\S-1-5-18 for each PXE request that it services on the network. This occurs whether the device sending the PXE request has a Task Sequence deployed to it or not. The generation of files will continue and may consume available hard disk space.
This occurs whenever a self-signed certificate is used for the Distribution Point (DP).
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.