Under the CMB method, it sounds like the calculation gives the same expansion rate everywhere. Under the Cepheid method, they get a different expansion rate, but it’s the same in every direction. Apparently, this isn’t the first time it’s been seen. What’s new here is that they did the calculation for 1000 Cepheid variable stars. So, they’ve confirmed an already known discrepancy isn’t down to something weird on the few they’ve looked at in the past.

So, the conflict here is likely down to our understanding of ether the CMB or Cepheid variables.

Except it’s not that they are finding the expansion rate is different in some directions. Instead they have two completely different ways of calculating the rate of expansion. One uses the cosmic microwave background radiation left over from the Big Bang. The other uses Cepheid stars.

The problem is that the Cepheid calculation is much higher than the CMB one. Both show the universe is expanding, but both give radically different number for that rate of expansion.

So, it’s not that the expansion’s not spherical. It’s that we fundamentally don’t understand something to be able to nail down what that expansion rate is.

Thanks. Based on some of the other answers, particularly in https://sh.itjust.works/comment/12511, I know understand better.

I appreciate everyone helping to explain some pretty basic questions in such detail.