Bug with fight order or is it intended? (in General)

Play-by-play
Goldminer Munchkin
Gold Mine cast Dispel Magic on all enemy Minions (2313)
Mystic Munchkin cast Dispel Magic on all enemy Minions (2784)
Holy Munchkin cast Ablative Shield on all friendly Minions (2913)
Mystic Munchkin cast Protection on all friendly Minions (6)
Ranged Combat
Gold Mine's familiar's Fireball hit Holy Munchkin's familiar [161], Holy Munchkin [736], Mystic Munchkin [533], Munchkin with a knife [566]
Gold Mine's Fireball hit Holy Munchkin's familiar [407], Holy Munchkin [1053], Mystic Munchkin [705], Munchkin with a knife [749]

Gold Mine's familiar's Fireball hit Holy Munchkin's familiar [328], Holy Munchkin [454], Mystic Munchkin [837], Munchkin with a knife [408]
Gold Mine's Fireball hit Holy Munchkin's familiar [390], Holy Munchkin [980], Mystic Munchkin [836], Munchkin with a knife [1018]

R.I.P. Holy Munchkin

Gold Mine's familiar's Fireball hit Holy Munchkin's familiar [352], Mystic Munchkin [803], Munchkin with a knife [789]
Gold Mine's Fireball hit Holy Munchkin's familiar [527], Munchkin with a knife [860]

R.I.P. Mystic Munchkin

Melee Combat
Gold Mine's familiar's Fireball hit Holy Munchkin's familiar [437], Munchkin with a knife [2585], Gold Mine [937]
Gold Mine's Fireball hit Holy Munchkin's familiar [890], Gold Mine's familiar [1131]

Holy Munchkin's familiar bruised Gold Mine [790]
Munchkin with a knife lacerated Gold Mine [6124]
Munchkin with a knife eviscerated Gold Mine [4085]
R.I.P. Gold Mine's familiar, Gold Mine R.I.P. Munchkin with a knife

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At melee round, I have offensively
Slot 1: Gold Mine's Familiar
Slot 2: Gold Mine
He has defensively:
Slot 1: Munchkin's familiar
Slot 2: Munchkin

I suppose the fight is in this order:
1. Offensive Slot 1 fight
2. Defensive Slot 1 fight
3. Offensive Slot 2 fight
4. Defensive Slot 2 fight

But the fight is more like this:
1. Offensive Slot 1 fight
2. Offensive Slot 2 fight
3. Defensive Slot 1 fight
4. Defensive Slot 2 fight

Is it intended? It seems illogical that offense slots attack first and defensives attack only after all offensive slot done. I always thought offensive slots are matched to defensive, to make it fairer.

Please enlighten me.

Actually, the fight is "all slots fire at the same time per round", and (in case one of the targets dies), the next "slot" (or how you call it) triggers at the next target in the same round.

I must say, this fight order copy-paste is a bit confusing to read (try copying the source code instead and posting it as HTML, not cleartext).

Well, this is what happens:

In the start of melee round, my familiar fights but not die. However, the defense familiar doesn't fight at the same time. It waits after my 2nd slot minion fights and kills my familiar. Only then, the defensive familiar and 2nd slot minion start beating my 2nd slot minion.

If you say all fight at once, then the defensive familiar should attack my familiar first since my familiar has not died from the 2nd slot offense. It doesn't make sense to me but may be to Jon. I may assume too much.

I suppose you mean only melee round ?
I looked a bit closer, and here's what I see...

I see that your familliar hits you with 937 FB friendly splash damage, you hit your own familliar with 1131 FB friendly splash damage, your familliar already has died from that damage (so no need to apply any more melee damage to it), then his familliar attacks you (you just killed your own familliar), then he attacks you (even though he also just died / will die in this round).

As I said - everybody attacks at once (regardless if dying this round or not), then damage from each minion is applied where there is any HP left to apply the damage to...

In that case, the fight is:
1. Offensive Slot 1 fight
2. Offensive Slot 2 fight
3. and so on...
4. Defensive Slot 1 fight
5. Defensive Slot 2 fight
6. and so on...

To sum up, all offesive slots fight first. Then defensive slots fight last.

Actually...

while (somebody alive on each side) repeat {
- all attackers that entered the round and can fire/hit do it
- apply damage dealt to defenders and friendly fire to attackers
- all defenders that entered the round and can fire/hit do it (even the ones that just died one step above)
- apply damage dealt to attackers and friendly fire to defenders
}