Hitachi-LG LDS-01 On Up Board Via USB

Running ARC directly on an Up Board (Windows, drivers from Up Community installed), I’m trying to get a Hitachi-LG LDS-01 working with the Hitachi-LG LDS Lidar skill over USB-UART. Wiring is LDS TX->USB-UART RX, RX->TX, GND common; power is a separate 5V/2A buck from the robot battery (grounds tied). I’ve tried two adapters (CP2102 and FT232RL), short shielded cables, and also a powered USB hub. In the skill I’ve set BaudRate to 230400, Offset Degrees 0, and have experimented with both "Set variables with location data" and "Fake NMS Pose hint event."

The skill connects, the LDS spins, and the Level 1 Navigation Viewer shows points, but I get periodic bursts of bad data: about once a second the distances drop to zero or jump wildly for a few scans. If I enable "Advanced communication parsing," I see intermittent checksum mismatch messages aligning with the spikes. CPU is <20%, so it doesn’t look like overload. Disabling Windows USB selective suspend and trying different COM ports didn’t change it. FTDI advanced settings (latency timer 1-16 ms) didn’t help either. Offset Degrees works, but I’m not entirely sure if positive is clockwise or counterclockwise, and I don’t want to mask a parsing issue by rotating the cloud. Also, with "Fake NMS Pose hint event" enabled, Better Navigator still occasionally pops a "No pose provider" warning even though scans are flowing.

Before I go the Arduino-bridge route, I’m hoping someone has this combo stable on an Up Board: what USB-UART adapter and exact Hitachi-LG LDS Lidar skill settings (baud, Offset Degrees sign convention, Set Variables vs NMS, and Fake NMS Pose hint) have proven reliable so Better Navigator consumes clean scans without checksum bursts or pose warnings?