What is the reason for setting flaps 1 on the ground at high temperatures? Yesterday I've seen an A320 standing at the gate with flaps 1. While this question answers, why the flaps should be up, is there any reason to retract the flaps to 1 instead of up?

In addition it seems to apply only in high temperatures (30°C, and rising yesterday). As well in this pilot eyes video the FO confirms the temperature (31°C) before setting flaps to 1 as they taxi to the gate.

I've seen this only on the A320 (yesterday) and on the A330 (in the video). Does this apply only on Airbus aircraft or as well on others?
From the A320 Flight Crew Operating Manual (FCOM):



And the image to text:


  On ground, hot weather conditions may cause overheating to be detected around the bleed ducts in the wings, resulting in “AIR L (R) WING LEAK” warnings. Such warnings may be avoided during transit by keeping the slats in Configuration 1 when the OAT is above 30 °C.


(Emphasis mine)

Basically it lets the leading edge anti-ice [hot air] leak sensors breathe, and not display a false positive.

Note that moving the lever to 1 from 0 or 2 at slow speeds (on ground) is called config 1+F, which deploys the flaps as well as the slats (see below).