Lots of items are able to be placed on glass, which are not supposed to be.
Try putting all the items in the picture attached, on glass. I'm %95 positive you shouldn't be able to place these items on glass blocks. (Not tested on glass panes, or other opaque blocks)
iPod Touch 5th gen (iOS 9.3.5) MCPE 0.16.2
Linked Issues
Created Issue:
Lots of items are able to be placed on glass, which are not supposed to be.
Try putting all the items in the picture attached, on glass. I'm %95 positive you shouldn't be able to place these items on glass blocks. (Not tested on glass panes)
iPod Touch 5th gen (iOS 9.3.5) MCPE 0.16.2
Added Linked Issues:
duplicates

Some of these are valid, like toches and redstone on top of the glass. But In addition to these, torches can also be placed on the side of glass blocks, which according to wiki should not be allowed.
Thank you for your report!
However, this issue has been closed as a Duplicate of
MCPE-16872.It has been linked to this report. If you have additional information, please add it to that report.
Please search before reporting, as it's likely that one exists already.
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I did search. Wtc