Eye-AF very inaccurate under low light (iso 3200 onwards)?

have switched to Sony a6300 since 4 months ago and really love the eye-AF a lot. However, the precision of its AF seems to be overhyped. Under low-light conditions (e.g. 1/125s, iso3200), the focus doesn't seem to be on-point (even though the camera shows the right AF point when zoomed in).

Anyone else experienced the same issue? What would be the next best alternative?

Tried Flexible Spot, Small, and it hunts quite a bit. If I choose Medium, then the precision is gone (I shoot people, so AF is always on eyes).

Appreciate any advice (other than manual focus). Thanks!

I don't have a 6300, but in my experience with Eye-AF on the A7Rii, it's either working or it's not (and when it's working, it works VERY well, with the exception of occasionally grabbing focus on eyebrows instead of the eye itself). I'm not quite sure I understand why you're trying different focus types, flexible spot small medium etc... Those modes have nothing to do with Eye-AF. Eye-AF can be engaged regardless of what af type you're using, and it overrides everything else. In other words, once you've engaged Eye-AF, it should place the tiny green square on the subject's eye and all other remnants of your focus point are gone. If you're still seeing your Flexible Spot, regardless of what size you've selected, Eye-AF is not engaged.

Also, what aperture are you having problems with eyes being OOF, and are you using AF-C or AF-S?

Eye AF works extremely well under most circumstances - saw a wedding photographer using it the other day, nailing every single shot with the 85/1.4.

I just wish they'd release a firmware update to allow it to recognise animal eyes as well as human. I rarely shoot people, and the system doesn't recognise giraffes/bears/iguanas​.

But that's probably more a feature for the A9, to be released with a 600mm prime or 200-500mm zoom...