Same kind of problem with Xcode 12.5.1 (12E507).
Two nested structures with more than 3 properties and 3 more properties is too much and will throw no error - most of the time. Erratic behavior but extremely disabling.
Sabearts
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
From
Belgique