Here is the workaround, sort of
In order to get access to all the available plot syles through the block attribute editor properties dialog plot style picklist you have to:
Go into the block editor and set the plot style of the attribute.
Exit the block editor
Perform the same operation meaning go back inside the block editor and assign the next desired plot style to the attribute.
After you have repeated this process to assign all the plot styles one by one you will be able to have access to the plot style through the block attribute editor properties tab.
The caveat is that if you copy the block or insert the block into a new drawing, not all the plot styles will be available, some but not all.
I will submit a case for this in the hopes it will eventually get fixed.
Best Regards
-Tim C.