FWIW, I asked gpt-oss-120b this question 10 times and the answer was always "sauce", "sane" or "sale". I also tried different temperatures (from 0 to 1), which did not seem to have an effect on the correctness of the answer.

EDIT: I now have also questioned the smaller gpt-oss-20b (free) 10 times via OpenRouter (default settings, provider was AtlasCloud) and the answers were: sage, sane, sane, space, sane, sane, sane, sane, space, sane.

You are either very unlucky, your configuration is suboptimal (weird system prompt perhaps?) or there is some bug in whichever system you are using for inference.