It seems every picture we see presents a different build. This one seems to be mid way in the life, with PCBs for the buffers but not the volume control.
So, this one doesn't have a ground lift, but has an input select switch.
There is solder on the Earth pin of the power socket, but I can't see whether there is a ground lead grounding the chassis. Use of black wire doesn't help. In principle any internal ground lead should be green or yellow-green stripe. It should go to a separate ground point bolted through the chassis.
Direct soldering of mains wires to the power supply is pretty awful. Using a proper connector would have added a few cents to the BOM. Use insulated crimped connectors to connect the the IEC socket, add a proper earth connection and you have a close to spec mains connection. $1 on the BOM and probably a couple of minutes onto the build. It would avoid any exposed mains inside the box. Nasty surprises like exposed pins with mains on them are again, just plain bad manners.
Lack of an on/off switch remains an odd design choice. It leaves the power supply running 7x24x365. Stress on the input stage of the PS from junk on the mains is always there. Given the DC coupled nature of the entire design I wonder if avoiding a power switch is a cheap way of avoiding turn on thumps.
We can see where the crosstalk comes from. There is a pretty basic mistake made with the lead dress of the balance pot. The two channels are twisted together. Perhaps this was done with some idea about resisting interference, but it isn't the correct way of doing it, and the coupling of the two wires is pretty much guaranteed to result in crosstalk.
There are a couple of places where red wires seem to have lost insulation. This is really odd.
There are a few grainy looking solder joints that look less than happy.
There is a length of green wire or insulation lying in the bottom.