The code on my trusted devices disappeared too quickly to read!
I had 4 trusted devices on my list. One is a very old Iphone SE I no longer used and usually sits without any power left in it in a box. One is an iMac, about 5 years old but recently updated to Sequoia. Then I had a new iPhone and a 2 year old Macbook Pro. The Macbook Pro broke last month, so I had it repaired and thus it was not signed into my apple ID the other day. Then I moved into a location without wifi, so I needed to use my Iphone hotspot, but it was not working on either computer. Thus, I factory reset my phone, and when logging in I had to perform 2-step authorization.
However, my macbook pro I was not able to receive it on, I had just been too busy with the move to sign back into everything on that computer after getting it back from Applecare. But when the code would appear on my desktop or even recharged Iphone SE (using a friend's hotspot), it would flash on the screen for only a split second before disappearing. After countless attempts, I was only able to get it to work by taking a photo with my old iphone in that split second window. Interestingly, first logging into my macbook pro, I noticed it did not have the same issue when I then used that devise to login to my new Iphone.
This incident along with a few others over the past year or two has made me lose faith in Apple. This is a crippling error, get it together Apple!
iMac 21.5″, macOS 15.6