Klaus
I've been playing with the prerelease of 1.17, not for very high resolution panos but with an input file of only 8192 x 4096, simply to allow a sharper result when zoomed in.
I have the following line in my .xml file -
<view architectural="0.7" hlookat="0" vlookat="-6" fovtype="DFOV" fov="105" fovmin="60" fovmax="105" limitview="auto" />
Viewing the pano on my iPad Mini, if I zoom in and drag to display the zenith I get a misplaced tile appearing, aligned to the top left of the window, rather than at its correct position. Scroll back away from the zenith and the tile disappears.
If I remove the architectural mode everything displays correctly. Also, everything seems OK in Safari on my MacBook, with or without the architectural mode.
Regards
Andrew