ID 509408 - Attempting to load an animated geometry sequence with a changing vertex count causes a crash

Problem summary
Attempting to load an animated geometry sequence with a changing vertex count causes a crash
 
This can occur with animated alembic files and OBJ sequences that have changing topology.
 
Customer reported version
Mari 4.7v2
 
Customer reported platform
n/a
 
Steps to reproduce
 
1) Download the attached file, 'ChangingVertexCount.abc'

2) Launch Mari and try to create a project with the downloaded alembic
 
Expected behaviour
Mari should display an error warning the user that the animated sequence has changing topology.
 
Actual behaviour
Mari crashes.
 
Workaround
Unknown.
 
Reproduced by support
This bug has been reproduced in:
Mari 5.0v2 - Windows 10 - CentOS 7.9
Mari 4.7v1 - Windows 10
Mari 4.2v1 - Windows 10
Mari 3.0v1 - Windows 10 - CentOS 7.9 - regression
 
Unable to reproduce bug in:
Mari 2.6v5 - Windows 10
 
Note: Although Mari 2.6v5 does not crash, an error message is displayed saying that the topology is changing (however the buttons in this dialog cannot be clicked):