This problem affects external memory interface products on MAX 10 devices.
A partial pin placement assignment for DQS/DM pins may cause the following internal error in the fitter stage of compilation:
Internal Error: Sub-system: FCUDA, File: /quartus/fitter/fcuda/fcuda_zb_dq_placement_op.cpp, Line: 8303 m_placed_cell == io_cell
The assignment of partial pin locations is not recommended. The Quartus II software should have produced an error message instead of the internal error.