This happens on older CPUs lacking AVX2 (e.g., Intel 3rd-gen Ivy Bridge or earlier). Check your CPU specs. If you lack AVX2, you cannot run RC8 extra quality. Use --extra-quality=slow (fallback to SSE4) but expect 100% CPU usage.
: Automatically disables transmission if the called station's message is not decoded for four consecutive intervals. jtdx 22160 rc8 extra quality
The core "extra quality" comes from a significant upgrade to the FT8 decoder. The previous 3-cycle, 3-pass decoding approach has been replaced with 9 decoding passes What this means for you: This happens on older CPUs lacking AVX2 (e