To reproduce with 所:

Go to en.wiktionary.org and search for the character. You will see that there are entries for various languages.

Use curl or your favorite tool:
curl -X GET "https://en.wiktionary.org/api/rest_v1/page/definition/所" -H "accept: application/json; charset=utf-8; profile="https://www.mediawiki.org/wiki/Specs/definition/0.8.0""
for more clarity:
curl -X GET "https://en.wiktionary.org/api/rest_v1/page/definition/所" -H "accept: application/json; charset=utf-8; profile="https://www.mediawiki.org/wiki/Specs/definition/0.8.0"" | python3 -m json.tool | grep language

And you will see that chinese, korean, and vietnamese are omitted. I do not know if "translingual" should be counted, but I expected the chinese definition to be available. I saw the same results with 愛，我，一，and 他.

If someone can point me in the right direction, I'm more than happy to fix this in late may.