OKCash split transaction into two outputs

[nmmmnu]

I am staking OKCash and every few days, my unspent output is split into two outputs.

Here in OKCash blockchain and I noticed something even stranger:

Just like in my case, this stake "spited" into two outputs,

https://chainz.cryptoid.info/ok/tx.dws?90071199653fe70443f5c3b916f31605d91004b6266c4b53a880e0a6d4f5c129.htm

While this stake "merges" together into single output,

https://chainz.cryptoid.info/ok/tx.dws?3103898.htm

But this remains OK:

https://chainz.cryptoid.info/ok/tx.dws?3103901.htm

Why this happens?

Does OKCash stake with outputs or with total amount?

Wouldn't be more profitable if I merge the outputs into single output?