I use the APP like A LOT. This have this big bug for a while. I waited a couple of update with hope that someone saw it, but no luck.
Step to reproduce:
1- Have at least 1 tracking already on the app
2- On the main list, swipe to mark as completed.
3- Add a new tracking:
3A- Enter any name
3B- On tracking numer I use the SCAN option. (I copy the tracking number from ebay, amazon or other purchase page. I paste it on a barcode generator page) I scan from computer monitor and the number apear correctly on the number bar.
3C- Select the provider (this bug works either if you dont select the provider, select a wrong one, or the correct.)
4C- Tap on SAVE
4- You will see the over text saying "Updating [Deliver name]" but on the list you will see the delivery name that you marked as complete seconds ago. The override text will say updated. But still on the list the old package. Restarting the app (just exiting or killing it) wont fix it. After restarted the app. If you do it again may be work.
Some times, if I enter to a deliver, hit the 3 points (options) and then "estimated delivery date" when you go back to the main list the deliver is gone.