Op, I used to teach beginner teachers about behaviour management.
let me talk you through the system at my school.
firstly, officially all kids were meant to be given a warning first before they got a detention.
but depending on the behaviour going straight to a detention was allowed.
fir example, imagine Freddie had brought a knife into school and had just killed Amelia who sat next to him.
should the teacher give a warning? “Freddie, you are not supposed to kill preople. This is your warning, if you kill anyone else in my class it’ll be a detention”.
no, this is clearly absurd.
I’m sure you can think of many other instances where a warning just isn’t appropriate - for example the child may be talking but what they are actually saying is eg “the teacher is a f’ing c word” etc in which case they don’t get a warning for talking they get a detention for swearing at the teacher.
now moving to look at cases where kids are talking, it is very very common for kids to get wrapped up in their own conversations and not even notice the whole class is staring at them wondering why they are broadcasting their whole conversatoon.
in one particularly funny occurrence two year 10 lads hadn’t noticed the whole class go silent except for them and we were all listening to their conversation about whose party they were going to on Saturday night. Honestly it was riveting.
They were very embarrassed when they realised literally everyone else in the room had shut up following my “5 4 3 2 1” and they hadn’t even noticed.
lots of kids again are given a warning but don’t realise it is a warning. If your kid is autistic this might be them,
so if the teacher says anything along the lines of
”next time it’s a detention”
”Johnnie you are disrupting the class be quiet”
etc this is a warning, they’ve had to speak specifically to your child about their behaviour,
now in practice my school was full of argumentative wotsits so we suggested to teachers that they stop the class, say to the kid “Johnnie this is your warning stop that now” simply so there were 30 witnesses and it was very very clear to Johnnie.
even then you’d get kids arguing with it.
so, in conclusion:
your kid was talking
you know he was talking
i wasn’t there you weren’t there so I don’t know if he got a warning but I’d put at least a fiver on that it did happen and he just either was so involved in his conversation he didn’t hear it at all OR he just didn’t process that being told to shut up is a warning and then he kept talking.
honestly, don’t take this further.