Problems with sort order when sharing a collection

It's probably not a bug, simply a misunderstanding about how the order is set for shared albums. A shared album will exist in all of the cloud apps that a user might use (LR Desktop, LR Mobile, LR Web) as well as in Lightroom Classic if that is also synced to the user's cloud space. However, each of those apps contain various sort order options, so it's entirely possible to be dispaying the same album in a different order in each of the apps (remember, images are not IN any set order - they're likely scattered all over the place on the storage device - they are simply displayed/listed in one of the various options that are available). So with that in mind, how then is the order set for shared albums that the viewer will see whenever they look at that album? The answer is that whatever has been set as the "Custom Order" is always used in the Shared Album.....the custom order can be set in any of the client apps, and it should sync to all the other apps, but in order to view it in the other apps the sort order, obviously, has to be set to "Custom". It's therefore entirely possible that at some point you may have set a custom order for that album, which is probably different to the capture date order that you happen to be viewing the album in on your iPad. 

To get the shared album into the order that you want, switch to Custom Order on the iPad where you should be able to drag and drop the images back into the order that you want. However, by far the easiest way is to logon the LR Web app (using your account details at lightroom.adobe.com) using any browser on any computer and select the album in question. In the grid click on the "Display" tab at the bottom (looks like an artist's palette), that then will display the current custom order that is being used for the shared album viewers, and will also show you a tool dialog. Expand that, and you will see that there's an option to Reorder the album using a variety of criteria, one of which is Capture Date. If you select any one of those options, that will reset the current "Custom Order" across all your cloud apps to match whatever order you've chosen, and that will be the order that the viewers will see.