Due to a problem in the Intel® Quartus® Prime Pro Edition Software v21.4, you might see the following internal error when the design uses clocks from multiple partition inputs that are actually connected to the same flat clock source.
Internal Error: Sub-system: LAB, File: /quartus/legality/lab/lab_fm_40_config_creator_module.cpp, Line: 1513
LCB SOLVER COULD NOT FIND A SOLUTION. CHECK DEBUG
An illegal LCB was detected.
A modification to the atom netlist that was not legalized was made in Stage: Retime.
This problem affects designs targetting Intel® Agilex™ FPGA devices.
To work around this problem in the Intel® Quartus® Prime Pro Edition Software version 21.4, combine such duplicated input ports into one.
This problem is fixed starting with the Intel® Quartus® Prime Pro Edition Software version 22.2.