Due to a problem in the Intel® Quartus® Prime Pro Edition software, accesses to transceiver reconfiguration registers may fail when connecting the reconfiguration interface to another Avalon-MM master in Platform Designer. The interface default Read Latency is incorrectly set to '0', which doesn't match transceiver reconfiguration interface behavior.
This problem exists in multiple transceiver related IPs, e.g. Transceiver Native PHY Intel Arria® 10/Cyclone® 10 FPGA IP, Intel Arria 10/Cyclone 10 Hard IP for PCI Express, Intel Stratix 10 E-Tile Transceiver Native PHY, L-Tile/H-Tile Transceiver Native PHY, Intel L-/H-Tile Avalon streaming for PCI Express.
To work around this problem, modify the Read Latency of the reconfiguration interface to '1' manually.