So consider this a noob question, but I've been playing for a little while now and today for the first time I noticed a little lightning bolt above 2 of my units, and in another game i'm in I noticed it above two units of another player......sorry if its a noob question but what is it ? ( it's a red circle with a white lightning bolt) thanks
Its the update, they have added an animated timer in battles.
The little red-and-black lightning bolt icons mean the opposing two units (or unit stacks) are locked in direct ground combat ("melee") until the battle is resolved.
Ground units only "attack" once per hour during melee combat, so the countdown ticker is the time remaining before the attacking unit stack applies its attack values to the defending stack again.
It may be that both units are attacking each other simultaneously, such as when two moving unit stacks run into each other. In which case, both opposing units (or stacks) will have a countdown ticker.
FYI, artillery units (including naval gunfire from BBs, CCs and DDs) only fire for effect once every 60 minutes, so they also have countdown tickers.
Aircraft units on patrol have 15-minute countdown tickers, but they only apply 1/4 of their attack values every 15 minutes.