1 I dealt with during parent-teacher and outright asked him to come up with 1 positive about my son
This was my first EVER parents evening with ds. Late August baby and he's in school half a term.
It was a catalogue of his faults.
One included "during assembly the head teacher asked what was on the card she was holding - and ds said a tractor without putting his hand up"
Ok, not exactly behaviour I'd be encouraging but when I asked if he'd yelled out she actually said herself head was stood right in front of him with card when she asked and he answered in a normal voice.
He'd mistaken her for talking directly to him.
Plus loads of other things where ds has been a 4yo.
She couldn't answer when I asked if she had anything positive about him?
This went for weeks more - daily complaints about his behaviour. I was obviously very concerned. Called a meeting with Ht (knew I'd get no where with teacher). Outlined all these things, asked if we could come up with a plan what we could out in place. Wanted to get on top of it before it got worse and while still year R.
Then I get told nothing wrong with his behaviour and stop over reacting 
So I told them to stop telling me everyday about everything he did that was normal for a 4yo if it didn't matter and he'd learn.
But then his teacher would write things in his home school book like "I think mininwierd is bored of his lunches as they are the same daily. Could you make him a varied lunch"
So I did. This wasn't easy as he didn't like sandwiches and insisted on the same each day (probably due to autism)
Cue a week later. DS isn't earring lunch because you keep sending him food he doesn't like/want to eat/ isn't what he expected.
She just didn't like him. Luckily because ds is actually very quiet and polite every year since then I've only heard good things.
So I've been there where I've heard it the other way round too and you don't recognise this apparently feral child from the one you know that barely spoke!