High side current indicator/
Overall the simplest solution would be to deploy one of the high side current sensor chips from TI or other vendors of such parts.

That said the problem with the solution that you have tried is that at no current the inputs of the IC chip are at 0V. There is always an offset voltage in the differential input section of the device which may be negative or positive. In one polarity the offset voltage make the differential section look like it should drive the output high. In the other polarity the offset voltage would make the output be high.