Why did MCegP9249sWMXY5Pf6Y75drjTSHnVS6THr got paid 24.06 Monacoin from the mining pool?

That' neither weird, nor something sinister nor a bug. I was contacted by a miner and he proved that he got a bit shafted by that block mess yesterday with his shares getting pushed out the window. I've sent him some compensation and that big amount you see there going to the address you've listed went back to the pool's change address. This transaction is also listed as latest payment on the Monacoin Pool's Payments list and includes the compensation I've mentioned and the left over balance of the miner.

foo@revolver /cluster # mmonacoin-cli listaddressgroupings
[
  [
    ...
    [
      "MCU9NDmdPz4HbfDEdbij7A48ho1D4NMPV3",
      0.00000000
    ],
    [
      "MCcpCDVsCUQsA6wpwQo4tYdCjMxMZqbFPh",
      0.00000000
    ],
    [
      "MCegP9249sWMXY5Pf6Y75drjTSHnVS6THr",
      24.06471174
    ],
    [
      "MCp4PkjM4DLksvGbtU6r627WpgUzjTsfkC",
      0.00000000
    ],
    [
      "MCrg85dHWg58QrmGE7Epcm5hcAbUoTwAFF",
      0.00000000
    ],
    ...
  ]

]

When funds get transferred using Bitcoin technology or anything that its derived from Bitcoin, the daemon attempts to sent it from unspent inputs. If it cant find an unspent input that covers the amount to send, it sends the smallest one it has and requests the change to be returned to a new address. In this case the input was an entire block reward.

Thank you for you quick and detailed reply. That makes sense.