This was just posted over at the .com:

Hi guys,

For those of you experiencing crashes when leaving a battle, please try turning off sound effects. We are currently working on a fix which we will distribute as soon as possible.

Thanks,

Mark O'Connell
(aka SenseiTW)
The highs and lows of hotfixes. My land battles now work, but my naval battles CTD after the results screen. I'll try this workaround in the meantime.