Missed Signs
It is agreed that each individual item is easily missed by each individual but it is the combination of oversights that is unlikely. Add to this in the same sequence with the same system, a very experienced eng has to deviate from the usual practice and it becomes, I think, very unlikely.
Re the video, the accident aircraft did partially pressurise to a differential of just over 1 psi - the reconstruction flight stabilised at just over 1 psi with the same setting as the video test where the cabin stabilised at just over 1 psi diff with the OFV posn as recorded on NVM and as found at impact so it looks pretty reasonable and a side test has shown that the fluctuations are very noticeable even with it twice that far open.