Rev counter fault or fault diagnostic?

[PieEater]

Riding home  my rev counter started switching from 7k to 5k to 0 then back to 7k 5k 0.
It did eventually go back to normal  but was it highlighting a fault code  or just playing up?

What bike is this for? There is no 5k Tacho code on the Gen1 thou, 7k is the EXUP.