Not true of non-US companies. I had also added money to Deepseek, and it was still there (and Z.ai and Moonshot are the same). I'm reasonable though, if it's been 5 years or something I might have understood, but it was 1 year and the account was in use during that time.

Where I live (in Canada) it's actually illegal for gift cards to ever expire, and there's lots available from US companies, so if it's an accounting issue other companies have figured it out.