A320 CATIII dual to CATIII single due turbulence

[A320 Flyer]

Can any A320 drivers elaborate on why after a period of moderate turbulence the STS page displays CATIII single only - INOP systems CATIII dual.

I remember from line training that I has something to do with the ADIRU system but I can find anything in the TOMEs that explains why

[latetonite]

A driver on type probably does not have the answer. Ask a pilot.

[Rocket3837]

I do not think it has anything to do with turbulence.
We used to cycle A/Ps prior to arming Apr. If ap1 engaged disengage it and engage ap2 and vise versa. Most of times the problem is solved.