Why do I incorrectly read "X" when simulating memories using altera_syncram in the Synopsys* VCS* simulator?

Description

Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 21.3 and earlier, you may observe an incorrect "X" value on the output data in the altera_syncram simulation model block. This problem occurs when you turn on X-prop mode in the Synopsys* VCS* simulator.

Resolution

To work around this problem, exclude the altera_syncram module from the Synopsys* VCS* simulator X-prop mode.