I test drove a 40th anniversary GTS-T R33 in standard trim and with a little spin of the wheels mid corner the "slip" light and "A-LSD" light both came on when wheels were spinning. But, both lights went out as soon as traction was regained. My thought was that they were only an indication that,
1. The "slip" light was a sign of loss of traction, and
2. the "A-LSD" was actively controlling the drive of both wheels.
If memory serves, the"SLIP" light was green in colour and the "A-LSD" light was orange.
Most "warning" or "system fault" lights are red on the dash of most cars, so I dont think that there is a problem with the diff itself, it should be running pretty normal.
The computer on the other hand..... well...... um.......