Model Relationships Customer Layout disappeared after upgrading to Power BI Desktop 2021 Oct version

I have a few report packages which each contains huge amount of tables. Previously I have already used several "Customer Layout" pages to manage the relationships within the data model for those reports. Below is one big report package as example: 

Before Oct 13, 2021, the relationships diagram in different custom layout pages, just works fine (see the sceenshots above). 
In the day Oct 13, 2021, Power BI desktop was upgraded to the new Oct version. (At the very beginning I installed Power BI Desktop from Microsoft Store. Every month's new version was installed automatically background.)

After this Oct upgrading, all the relationship diagrams in different customer layout pages are gone.

And even serious problem is that: 

if I re-do or create any new customer layout, and then save it.

And if I close it and then open the pbix file again. Nothing can be shown from there. This is a surprising behaviour! 
Assume something is wrong after this month new release. 

Before I posted this, I have also tried to uninstall and reinstall Power BI Desktop (from Microsoft Store), but the issue is still existing after the reinstallation. 

As this is quite key for handling relationships within data model, normal working cannot go on if this issue cannot be solved. 

Can anyone please look into this issue ASAP and suggest how to move forward? 
Many thanks!