Would an A320 override the autothrottle due to an erroneous radio-altimeter?
The Airbus thrust levers can only be moved manually. The levers do not move on their own to reflect the auto-thrust setting.

There are detents for the different modes of auto-thrust operation. Regarding the RETARD mode whereby the thrust auto-idles, Airbus doesn't use that (except in autoland).* Hence the callout, "RETARD, RETARD," for the pilots to retard the levers before touchdown.

In a normal uneventful flight, the third detent from the top (CL) is where the thrust levers stay throughout the whole flight from thrust reduction after takeoff, to just before touchdown.

(A320 manual)

* Airbus released an Operations Engineering Bulletin (no. 38) in Mar 2011 (also see the Airbus brochure on the matter). What happened to the Turkish 737 could happen to an A320 due to an "erroneous radio altimeter height indication".

Still, in the scenario given once the pilot flying had applied full power (TO/GA detent) it would have stayed there (unlike the Turkish 737).



Thanks to @user40476 for bringing up this autoland feature, which made me look up further details.