The only way to rule out the ui is to not involve the ui in the tests. From my point of view you are testing the ide, not your app. And I can tell you that I know that there are problems with the table editor in the ide, one of them (not the only one) is described here.
Were you able to reproduce the problem by checking the content of the table with the server console, without keeping the table open in the ide?
Or by adding a button on the form that shows the content of the last updated row in an alert?
Or by creating a second app that just checks the correct behavior of the first app?
I wasn’t, simply because all I know at this point is that you claim that there is a bug, but still don’t describe how to reproduce it or even how to check the correct behavior. You say something isn’t updated, but I still don’t understand what.
I’m not claiming there is no bug. All I’m saying is that there are tens of thousands of Anvil apps out there and it’s very unlikely (albeit not impossible) that you are the only one affected by this bug. And that there are thousands of users out there and we all are affected by the quirks and bugs of the ide. So I tend to (very strongly) believe that the problem lays either on the way you use the ide to test it, or on a bug in the code.