Why isn't a read-valid signal asserted and an error response returned when reading reserved register space? Whereas a valid signal and error response are returned when writing to reserved register space?

Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 23.3, you may see a read valid signal is not asserted and an error response is returned when reading reserved register space. In contrast, a valid signal and error response are returned when writing to reserved register space.
It's important to note that it operates in a non-functional state, and users will not encounter disruptions. This is ensured by a timeout mechanism, which triggers the return of some dummy response after the timeout.
 

There is no workaround.
This problem is scheduled to be fixed in a future release of the Intel® Quartus® Prime Pro Edition Software.