Due to a known problem in the Intel® Quartus® Prime Pro software version 21.1 and earlier and the Intel® Quartus® Prime Standard Edition version 20.1 and earlier, when using the JESD204B Intel® FPGA IP in TX mode with Intel® Arria® 10, Intel® Cyclone® 10 GX, Intel® Stratix® 10 and Intel® Agilex™ devices, if the product of F and K is the maximum value of 1024, configuring csr_lmfc_offset has no effect in shifting the internal LMFC edge of the IP. The internal LMFC counter defaults to start counting from 0 upon SYSREF detection.
To work around this issue, use the LMFC adjustment or RBD offset in the RX converter device to achieve deterministic latency when FxK=1024.
This problem is fixed starting with the Intel® Quartus® Prime Pro Edition software version 21.2.