Description
Due to a problem in the Quartus® Prime Pro Edition Software version 18.1 and earlier, you may see library definitions for VHDL entities with same name are ignored and a single entity is used in multiple instances irrespective of each entity is defined to separate libraries.
Resolution
To work around this problem, use unique name for each entity in VHDL.
This problem is fixed starting with the Quartus® Prime Pro Edition Software version 19.1.