Changing an Interface name to be the same as an existing alias name still lets the user apply the changes
1) Make an alias, e.g. ZLAN
2) Interfaces->LAN - change the description to ZLAN
A message is displayed "Sorry, an alias with the name ZLAN already exists." But actually the change has already been saved to config.xml. The "Apply changes" box and button is showing.
3) Press Apply
Now you get "Error loading the rules" notice.
This happens in 2.2.6 (and presumably earlier releases) and in 2.3. I will provide PRs for both.