We find our answer, but not sure why it didn't work.
Another page in our app DID update .bottominfo on success.
We compare the two, and found no difference other than order of setting parameters prior to display form.
Debugging in browser showed no errors of any kind, working or non-working page.
We copy working page to non-working and just have to close this.
Sorry, we cannot debug it to find out our time must go on our app.