Let me ask you this ─ did God at that time know that the result of the vow would be the sacrifice to [him] of Jephthah's daughter? If God is omniscient then [he] he indeed knew. (If God isn't omniscient but is omnipotent then [he] can make [him]self omniscient whenever [he] likes.)
And in that case God went ahead with the deal because [he] was happy with the price.
Againl... this sums it up. You are reading into it at the expense of all the contradictory evidence that three people have supplied you. You want robots as people.
So... He will remains as you see Him... however wrong you are.