Null object cannot be a converted to a value type.

[muramasarou]

画像の通りエラーによるアプリのフリーズが発生しましたので報告します。

エラーのログはこちらになります
error_log.txt

[myangelkamikaze]

Sorry for the slow reply.
Do you happen to remember what this battle looked like?

I had to do some adjustments, but it looks like your airbase killed all but 1 enemy, which was then killed by the opening torpedo from 木曾. After that, the api data is somewhat confusing. The opening torpedo from 阿武隈 doesn't seem to target anyone based on the api data. Can you remember if 阿武隈 did the opening torpedo attack?

[myangelkamikaze]

Technical notes:

api_frai_list_items (target index) for 阿武隈 was [null]. Here, we expect either null (didn't attack) or an array of integers for the targets.
api_edam (damage values) became Dictionary<string, double> instead of the expected List<double>. While most values looked the same as you'd expect from the list, it also had an additional value api_ which is the amount of damage 阿武隈 did.

"api_edam":
{
	"0": 0,
	"1": 0,
	"2": 0,
	"3": 0,
	"4": 0,
	"5": 0,
	"6": 0,
	"7": 177,
	"8": 0,
	"9": 0,
	"10": 0,
	"11": 0,
	"api_": 147
}

What I think happened here is an edge case where when 阿武隈 attack was supposed to be calculated, all enemies were already dead, so her value just got sent into nothingness.
This might be the visual bug with combined fleets when only a single ship fires a torpedo instead of all of them.

[muramasarou]

Sorry,
I don't remember. The only thing I remember is that I froze after the night battle phase.

[myangelkamikaze]

Night battle?
The battle should have ended after opening torpedoes.
Also, do you mean that the game itself froze? Or did only 七四式 stop processing data?

[muramasarou]

After the daytime battle, the screen went dark and the 'Continue' option became unavailable.
At the very least, the daytime battle did run, but I don't remember its details.