As an open-frame supply it’s not a touch-safe appliance and so not necessarily expected that the heat sinks would be bonded to AC earth potential, though I’d consider it a prudent design choice to do so.
As an isolated supply there shouldn’t be any significant DC potential between either the output GND or V1 terminals, and input earth terminal (J4) though it’s possible one might measure something like that due to some sort of rectification effect in conjunction with a high-impedance voltmeter and the AC leakage currents that do flow across the isolation barrier. It’d also be possible for external equipment to impose such a voltage between the two.
The serious issue is whether or not there is current flow, AC or DC, between the output and input of the supply. (heat sinks/shields don’t count as output terminals) I’d suggest checking for both AC and DC voltage between both output terminals and J4/earth, and then proceeding to measure current flow between the two. If you find any voltage present, you might want to use a resistor to protect one’s meter fuse in case something’s seriously awry.
Under no circumstances should you be seeing more than 1 mA of current flow (AC or DC) between either output terminal and earth GND without using any added series resistance. Depending on the spec to which the supply is built, as little as 10uA of such current flow might be unacceptable. I’d have to look into the spec a bit closer to see which 60601 limit applies. Regardless, if you see more than 1mA of current flow in that fashion, it’d be a very serious defect and I’d be consider anything upwards of 100uA cause for concern.
Again, we’re talking about measuring between input and output terminals here. The heat sinks/shields don’t count, though I wouldn’t blame a person at all for looking at different options if those heatsinks do prove to be electrically hot relative to input earth.
Please make those measurements and report what you find.