Something else could be bothering him. Or he hit his limit that day. My little man is like that too. If he's having a bad day, or is feeling sensitive, he will sometimes melt down over things that he generally does with no problem.

My son does that he refuses to say words when ask him. If he wants juice he will not say it instead he just cries and run away. Other he'll say juice without us even prompting him, he does use his words randoml, but refuses to do so when we ask it to.
It's very frustrating for me and his dad.
He also dealt in his receptive language.
However today he was in a funk mood and I said to him let go watch thomas he jumped clap his hand and head to the tv room. We were like wow he does understand us!
I need help with this too.
Good for you I'm a punk I give into the crying all the time it just breaks my heart.