Xilinx ISE 14.7 refuses escaped Verilog names in schematics, so the export wrote _opcode_0_, which ISE accepted but turned into an illegal VHDL port, and the import renamed it opcode_0, so the round trip cannot restore the original names.
From the Grok pain-radar digests, Oct 27-28 2026 (Oct 27 8:41 AM ET through Oct 28 7:41 AM ET digests plus the Haitch editions). Verified live 2026-10-28: issue/PR/thread read; title and state confirmed.