Kids have accidents.
At home too.
Maybe he is just more relaxed at home and 'forgets?'
That is common with this age.
They 'think' they can hold their bladder longer... than they actually can.
They do not yet have, perfect "deductive reasoning.'
He is young.
My son is now 5. He sometimes has accidents too. He thinks he can just keep holding it. Especially while playing.
My daughter that age, did too.
Their Teachers said, it happens. Kids get distracted. Not always self-reliant at this age, per their body.
But kids have accidents.
It is childhood.
Even at this age, their bladders/nerve connections/brain connections are still developing. It is not static.
Don't scold him.
Just remind him more.
Or maybe at home he simply is drinking more liquids, than at Daycare. Hence, he is having more accidents at home.