Its really weird indeed. As a player, I have no answer here, maybe you can ask support? 

Question: why did you send more troops if you were able to win with one dimacha? 

hi Gehard

if I remember correctly the weakest forces are hit first so in this case as you had used 3 weaker forces as wel as the Dimacha they were wiped out 

if you only need 1 dimcha to kill an EP then only use 1 Dimacha and that way you wont lose units you dont need to 

That is not accurate morteee.

Many of us send a single unit of each type to clear positions or for pvp combat because the game mechanics divide the damage between all units present - In a normal lower level positions, or divine positions, we send many single units and you take no losses, but if you send only 10 cav units you will loose 3 or 4.

If game mechanics applied damage to the weakest forces - this would not be possible for us to do.

This was reported to VIP support years ago.

The reply was that it is a known bug, but similar to the invite a friend issues, it is not a priority for them to fix at this time.

Hello Guys. We should send only  ONE dimacha  to the Elysian positions lower than 33 levels, depending on how high is our agreements for dimacha.If not upgraded dimacha, we have to send 1 dimacha to 30 position and lower. If we will sent 2 dimacha   we might lose one of them.Elysian Xerxes is tricky, and the game's mechanic was like this since the Elysian Positions have been released. Don't confuse the game's mechanics about elysian positions, the regular positions, and  Elysian's units combat for PVP, as they are totally different mechanics.                                             Gerald, it is not a bug it is just Elysian Xerxes.It is up to the players to do experiments to test the Elysian Xerxes, but they might lose their units in vain.  So, please, next time, use only one dimacha. Anyway, the lost units aren't totally lost, as they are in the Elysian bank. I hope you will get an Elysian Xerxes payout soon.🙂

thanks for the correction Banshee :)