Sorry, took me a while to test a few scenarios due to some mechanical work on one of the bikes.
Yeah, there's definitely sticky/ghosts watts, along with some general lag regarding power data - going by my fit files, there's about a 1s general delay, e.g. when rolling up to a hill and then putting the power down.
Presumably on top of that, there's sticky/ghosts watts when dropping to zero/coasting, resulting in about a total of ~3s it takes to actually drop to 0W (again, in the fit files).
Both behaviours look worse on the device as well as the displayed numbers ironically both update more regularly than the 1s fit file interval, but also seem to suffer from the device's (presumed) low processing power, so it's easily 5s on there while riding.
Those numbers are all based on a SRAM Rival PM - I've also tested with a Leoseek spider PM but that already comes with its own small lag so the numbers are slightly higher still.
There's also the issue that the "power gauge" widget (which is well-designed in theory) seemingly updates the gauge and the number bit separately from another, sometimes resulting in some weird changes (think power zone dropping to a lower colour while power value increases).
So yeah, maybe not the best device if you want to dive into power metrics - I think the overall averages, NP, etc. will still be okay, but it's still annoying especially mid-ride.
EDIT: Oh yeah, I also tried to connect the Leoseek PM via Bluetooth, but that just wouldn't work at all, so the suggested workaround might not be available depending on your PM hardware.