We had this happen with my kid. The teacher wasn’t able to provide much insight. So we made an effort to pay launch mire attention to DD’s writing. We realized that her grammar and writing structure was pretty terrible.
I’d recommend checking out every single piece of worsting your kid brings home this month, or look them up on Google Classroom. Go over them with your kid and make improvements, as needed.
MCPS doesn’t spend much time on grammar in the early years and it shows in some MCAP scores, I think.