This makes no sense unless the US expects ASML to ship EUV machines to China very soon, because now China will be prepared if they receive such machines later and it likely won't slow them at all. They will know to source materials elsewhere and I have little confidence in software export bans working in this day and age.
Surely the US would pick an inopportune moment to yank this away from China to inflict maximum chaos and delay development as much as possible. What prompted this to happen now? Are they about to acquire EUV machines somehow?