The case is Garland v. VanDerStok, No. 23-852. Here’s the transcript of argument. The government’s argument was brief and not interrupted by questions. Then came a lot of questions, and only Gorsuch seemed to be doubting the government position (see pp. 20-30), though Jackson raised some interesting questions (see pp. 53-56).

A good summary is at SCOTUSblog. The author thinks the regulation will be upheld.