The NumLock status may become out of sync during a Remote Desktop session.
In certain rare scenarios, when connected to a system using Remote Desktop, the status of the NumLock key may go out of sync between the host and client systems. This typically can be seen on slower dial-up connections or if system resources are low on either system. Repeatedly pressing or holding down the NumLock key can cause this behavior.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB958503.