TPE 3D uses Apple "Universal Links". Such links can be opened in either a native iOS App or in Mobile Safari. Your device will default to the most recent behaviour when opening links.
If you find that when attempting to use the "Open in TPE 3D" option in TPE, a page opens in Mobile Safari instead, you can do the following trick to switch your preference to have the link open TPE 3D directly.
Note: please do confirm that you have TPE 3D installed on the device, and that the app is updated (older versions may not support the Universal Link functionality).
To open in TPE 3D from Mobile Safari:
- Swipe down on the page to reveal the app "smart banner"
- If you have a suitable version of TPE 3D installed, the banner should show an Open button at the right
- Tap Open to open the page in TPE 3D
Here it is in action: