Error message, but no error

[letharo]

When adding a trail to a list during the trail creation, an error message is displayed, but the trail is added to the list as intended.

Steps to reproduce the error:
Create a list if none exists
Create a new trail
Upload a gpx file
Click on Save Trail
=> A confirmation is diplayed that the trail was saved and adding the trail to lists becomes available
Click on Add to list
Select any list
The selected list is shown under the trail's lists
Click on Save Trail
=> An error message is displayed that there was an error saving the trail. However, the trail was saved and added to the list as intended and expected.