When I tried to remove the water chiller to clean it, it developed a leak. Jason Newton cleaned it and fixed the leak and it looks as good as new! Reinstalled it and it's working great.

I performed a test cut at 60% power, and measured a current of 26.7mA through the tube.

While vacuuming and tidying around the laser, the laser tube's (-) terminal came off the terminal block at the power supply, evidently hanging by a couple strands. The current sensor was also dangling so I hot glued it next to the terminal block so the wires aren't strained. Reterminated the wires from the (-) to the current sensor and then to the power supply, all via the terminal block.

The wires to the ESP8266 Laser Tube PWM sensor are tapped into a terminal block on the end of the power supply. Apparently those screws were a bit loose because one of the wires came out. With no reference I didn't know where to hook it back up, so I disconnected that ESP8266 altogether. We haven't had a working InfluxDB server for some time, so this data wasn't being collected anyway. I intend to get this working again.