ID 532966 - Mask Icons are not always displayed after removing a Mask Stack

Customer reported version
Mari 4.7v4
 
Customer reported platform
Linux
 
Steps to reproduce
 
1) Open any project

2) Create a Color Layer

3) Add a Mask to the Layer (Right-click > Layer Mask > Add Mask > Hide All)
 
4) Turn the Mask into a Mask Stack (Right-click > Layer Mask > Make Mask Stack)
 
5) Remove the Mask Stack (Right-click > Layer Mask > Remove Mask)
 
6) Add a new Mask to the Layer (Right-click > Layer Mask > Add Mask > Hide All)
 
Expected behaviour
A Mask should be added to the Layer with an icon shown that can be clicked to target it.
 
Actual behaviour
A Mask is created, but no icon is displayed so it cannot be edited.
 
Workaround
The Mask icon will appear again if you lock and then unlock the Layer.
 
Reproduced by support
This bug has been reproduced in:
Mari 6.0v1 - Windows 10 - CentOS 7.9
Mari 4.7v1 - Windows 10 - CentOS 7.9 - regression
 
Unable to reproduce bug in:
Mari 4.6v4 - Windows 10 - CentOS 7.9
 
Earliest version tested
Mari 4.6v4 - This issue doesn't appear in this version and has regressed