While this being the most probable explanation, what else on earth could have happened? It's really hard to take this game as realistical when things like this happen

Escorts were set to the same altitude as bombers, target set to Vanua Lava, which is normal range away from Ndeni for both Zero models. Only CAP 10 and rest 10 (could they fly the CAP AM??). Stacking limit was not exceeded as far as I remember. There propably was no recon of the LRCAP in Luganville because of heavy CAP but it really is a known "fact".
AM, Zero aces sleeping on sake:
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Morning Air attack on TF, near Vanua Lava at 121,148
Weather in hex: Heavy rain
Raid spotted at 40 NM, estimated altitude 14,000 feet.
Estimated time to target is 15 minutes
Japanese aircraft
D3A1 Val x 35
Ki-45 KAIa Nick x 9
Allied aircraft
P-400 Airacobra x 10
P-40B Warhawk x 11
P-40E Warhawk x 28
Japanese aircraft losses
D3A1 Val: 24 destroyed
Ki-45 KAIa Nick: 2 destroyed
No Allied losses
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PM, zero aces woken up:
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Afternoon Air attack on TF, near Vanua Lava at 121,148
Weather in hex: Severe storms
Raid spotted at 34 NM, estimated altitude 14,000 feet.
Estimated time to target is 12 minutes
Japanese aircraft
A6M2 Zero x 30
A6M3 Zero x 29
D3A1 Val x 11
Ki-45 KAIa Nick x 4
Allied aircraft
P-400 Airacobra x 10
P-40B Warhawk x 10
P-40E Warhawk x 28
Japanese aircraft losses
A6M2 Zero: 1 destroyed
A6M3 Zero: 3 destroyed
D3A1 Val: 2 destroyed
Ki-45 KAIa Nick: 2 destroyed
Allied aircraft losses
P-400 Airacobra: 2 destroyed
P-40B Warhawk: 1 destroyed
P-40E Warhawk: 3 destroyed
Allied Ships
xAP Wanaka
xAP Anhui, Bomb hits 1
Aircraft Attacking:
4 x D3A1 Val releasing from 3000'
Naval Attack: 1 x 250 kg SAP Bomb
2 x D3A1 Val releasing from 2000'
Naval Attack: 1 x 250 kg SAP Bomb
2 x D3A1 Val releasing from 1000'
Naval Attack: 1 x 250 kg SAP Bomb
1 x A6M3 Zero sweeping at 11000 feet
6 x A6M2 Zero sweeping at 11000 feet