You need to check the notes at the bottom of the chart. The deaths always look low for the first 2-3 weeks. Only about half the jurisdictions report their deaths to the CDC within the first 10 days. Many take 2-3 weeks or longer. The numbers get adjusted as new reporting arrives. This always happens for every cause of death. Then there was severe underreporting for last week. I look at this chart several times a week, and last week was lagging way behind all week, when prior weeks (at the start of a new week) were more or less what you see here.
Happens every single week. Here's a comparison of how the data for the last 4 weeks of October changed between when it was reported on October 30th vs today:
October 30th:
Source
Same dates, but data as of today:
Source
The data gets updated as more jurisdictions report in. Even the data that was 4 weeks old at the end of October was only 90% complete then. CDC is only able to provide what the various jurisdictions report to them. If Bumfart, Kentucky takes 3 months to get their data sent out to CDC, there's nothing CDC can do about that except report what they have when they have it and give everyone a warning that it's incomplete for a while.