Platform Designer fails QDR II elaboration

This behavior began recently with a mature project. During QSys Generation, the process fails while elaborating a QDR II instantiation claiming it can't find "sequencer/sequencer.elf". Here's the error log:

Info: pll0: "qdrii_1" instantiated altera_mem_if_qdrii_pll "pll0"
Info: p0: Generating clock pair generator
Info: p0: Generating qsys_fabric_qdrii_1_p0_altdqdqs
Info: p0: Generating qsys_fabric_qdrii_1_p0_altdqdqs_in
Info: p0: 
Info: p0: *****************************
Info: p0: 
Info: p0: Remember to run the qsys_fabric_qdrii_1_p0_pin_assignments.tcl
Info: p0: script after running Synthesis and before Fitting.
Info: p0: 
Info: p0: *****************************
Info: p0: 
Info: p0: "qdrii_1" instantiated altera_mem_if_qdrii_phy_core "p0"
Info: m0: "qdrii_1" instantiated altera_mem_if_qdrii_afi_mux "m0"
Error: s0: Error during execution of "{C:/intelfpga/18.1/quartus/../nios2eds/Nios II Command Shell.bat} make all 2>> stderr.txt": child process exited abnormally
Error: s0: Execution of command "{C:/intelfpga/18.1/quartus/../nios2eds/Nios II Command Shell.bat} make all 2>> stderr.txt" failed
Error: s0: ]2;Altera Nios II EDS 18.1 [gcc4]C:/intelfpga/18.1/quartus/bin64/uniphy_mcc -ac_code sequencer_mc/ac_rom.s -inst_code sequencer_mc/inst_rom.s -ac_rom ../qsys_fabric_qdrii_1_s0_AC_ROM.hex -inst_rom ../qsys_fabric_qdrii_1_s0_inst_ROM.hex -header sequencer/sequencer_auto.h -vheader ../sequencer_auto_h.sv -ac_rom_init sequencer/sequencer_auto_ac_init.c -inst_rom_init sequencer/sequencer_auto_inst_init.c -DQUARTER_RATE=0 -DHALF_RATE=1 -DFULL_RATE=0 -DNON_DES_CAL=0 -DGUARANTEED_READ_BRINGUP_TEST=0 -DMEM_ADDR_WIDTH=22 -DHARD_PHY=0
Error: s0: UniPHY Sequencer Microcode Compiler
Error: s0: Copyright (C) 2018  Intel Corporation. All rights reserved.
Error: s0: Info: Reading sequencer_mc/ac_rom.s ...
Error: s0: Info: Reading sequencer_mc/inst_rom.s ...
Error: s0: Info: Writing ../qsys_fabric_qdrii_1_s0_AC_ROM.hex ...
Error: s0: Info: Writing ../qsys_fabric_qdrii_1_s0_inst_ROM.hex ...
Error: s0: Info: Writing sequencer/sequencer_auto_ac_init.c ...
Error: s0: Info: Writing sequencer/sequencer_auto_inst_init.c ...
Error: s0: Info: Writing sequencer/sequencer_auto.h ...
Error: s0: Info: Writing sequencer/sequencer_auto.h ...
Error: s0: Info: Writing ../sequencer_auto_h.sv ...
Error: s0: Info: Microcode compilation successful
Error: s0: C:/intelfpga/18.1/quartus/../nios2eds/sdk2/bin/nios2-bsp hal sequencer_bsp .. --default_sections_mapping sequencer_mem --use_bootloader DONT_CHANGE
Error: s0: child process exited abnormally
Error: s0: Cannot find sequencer/sequencer.elf
Error: s0: An error occurred
    while executing
"error "An error occurred""
    (procedure "_error" line 8)
    invoked from within
"_error "Cannot find $seq_file""
    ("if" then script line 2)
    invoked from within
"if {[file exists $seq_file] == 0} {
		_error "Cannot find $seq_file"
	}"
    (procedure "alt_mem_if::util::seq_mem_size::get_max_memory_usage" line 14)
    invoked from within
"alt_mem_if::util::seq_mem_size::get_max_memory_usage [file join "sequencer" "sequencer.elf""
    invoked from within
"set calc_mem_size [alt_mem_if::util::seq_mem_size::get_max_memory_usage [file join "sequencer" "sequencer.elf"]]"
    ("if" then script line 2)
    invoked from within
"if { !$do_only_rw_mgr_mc && !($bfm_mode || $hps_mode)} {
		set calc_mem_size [alt_mem_if::util::seq_mem_size::get_max_memory_usage [file join "sequenc..."
    (procedure "generate_qsys_sequencer_sw" line 924)
    invoked from within
"generate_qsys_sequencer_sw $prepend_str $protocol $pre_compile_dir $fileset $inhdl_dir $rdimm $lrdimm 0 0  $nios_hex_file_name $ac_rom_init_file_name ..."
    invoked from within
"set seq_mem_size_list [generate_qsys_sequencer_sw $prepend_str $protocol $pre_compile_dir $fileset $inhdl_dir $rdimm $lrdimm 0 0  $nios_hex_file_name ..."
    ("if" else script line 2)
    invoked from within
"if {[::alt_mem_if::util::qini::qini_value alt_mem_if_seq_size_request 0] > 0} {
		set seq_mem_size [::alt_mem_if::util::qini::qini_value alt_mem_if_se..."
    (procedure "alt_mem_if::gen::uniphy_gen::generate_qsys_sequencer" line 238)
    invoked from within
"alt_mem_if::gen::uniphy_gen::generate_qsys_sequencer "${name}" $protocol $tmpdir $fileset {}"
    invoked from within
"set qsys_sequencer_files_list [alt_mem_if::gen::uniphy_gen::generate_qsys_sequencer "${name}" $protocol $tmpdir $fileset {}]"
    (procedure "alt_mem_if::gen::uniphy_gen::generate_sequencer_files" line 3)
    invoked from within
"alt_mem_if::gen::uniphy_gen::generate_sequencer_files $name "QDRII" $tmpdir QUARTUS_SYNTH"
    invoked from within
"foreach generated_file [alt_mem_if::gen::uniphy_gen::generate_sequencer_files $name "QDRII" $tmpdir QUARTUS_SYNTH] {
		set file_name [file tail $gener..."
    (procedure "generate_synth" line 8)
    invoked from within
"generate_synth qsys_fabric_qdrii_1_s0"
Info: s0: "qdrii_1" instantiated altera_mem_if_qdrii_qseq "s0"
Error: Generation stopped, 63 or more modules remaining
Info: qsys_fabric: Done "qsys_fabric" with 45 modules, 58 files
Error: qsys-generate failed with exit code 1: 20 Errors, 4 Warnings
Info: Finished: Create HDL design files for synthesis

I've tried de-installing and re-installing Quartus 18.1.0 to no avail. I've included a stripped down project to see if someone can replicate the issue. Steps to follow:

1. Unzip to an empty directory.
2. Open project "cxp_upr.qpf"
3. Launch Platform Designer
4. Open "qsys_fabric.qsys"
5. Click "Generate..."

Many thanks in advance for your much valued assistance!