Illanair: Whenever I de-select a troop unit, the game plays this loud (and excessively long) bell ringing noise, followed by a jeering crowd.

This plays - EVERY time I de-select them, which is more often than you might think. Especially during combat with other factions.

What's worse is - This particular sound isn't tagged internally as either Effect or Ambiance, meaning the only way to get rid of it is to disable sound in the game completely.

(Copy from Steam thread)

(The exact sound - as played repetitively at around 40 seconds in)
https://www.youtube.com/watch?v=aOGMmA1SS3Y

Illanair: Yeah I read that on the Steam forums - Impatiently waiting to be able to enable my ingame sound again. :)