When entering a long master passcode, there seems to be a limit on how long a passcode can be displayed during entry. Once you reach that limit, instead of text entry continuing to the right, subsequent characters overwrite the last character visible. If the character being displayed at this point is wide (upper case W for instance) it is cut off by the cursor (W looks like V). There is still plenty of visible space between the point where entry stops and the lock icon.
The actual number of characters varies between the iPad Air and iPhone 5s. On the iPad, you can enter 16 characters and at character 17 on the entry remains in that one spot and cuts off wide characters. There is more than an inch of white space between where this happens and the lock icon on the right. On the iPhone you can enter 13 characters and character 14 on stay in that position. There is maybe a third of an inch of white space before the lock icon.
This might not have been new with beta 14, but I did notice it now.