ID 371284 - When exporting and re-importing session scripts from a specific project to a new one, Mari crashes.

Problem summary
When exporting and reimporting session scripts from a specific project to a new one, Mari crashes.
The bug is archive specific and it contains multiple channels with shared layers. 

If some layers of a Tri Planner Projection type are removed, Mari does not crash when importing the session script.

Customer reported version
3.3v1

Customer reported platform
Linux n/a

Steps to reproduce

1) Open Mari

2) Open the specific archive

3) Go to File>Session>Export Session and export the session script 

4) Create a new project with the provided geometry and select all of the objects

5) Go to File>Session>Import Session, select the exported script and chose Import>Onto Selected Object

6) Mari does not import the session script and it is crashing

Workaround
Unknown. 

Reproduced by support
This bug has been reproduced in:
Mari 4.2v1 - Windows 10 - CentOS 7 
Mari 3.3v1 - Windows 10 - CentOS 7 - MacOS 10.12
Mari 3.2v1 - Windows 10 
Mari 3.1v1 - Windows 10 
Mari 3.0v1 - Windows 10 - CentOS 7 

Earliest version tested
Mari 3.0v1 - This feature did not exist before this version

Expected behaviour
Mari should import the session script to a new project as intended.

Actual behaviour
Mari is crashing when trying to import the session script.