Just curious, if you run a "Refresh" (without doing anything else) does it update "Last Activity At" in the the device metadata? If so, that would solve the OP's problem, but then the question would be what's different between your two setups. If not, they'd either need to re-write the driver to change some attribute (which I think is the only way to generate "activity," and the Oh-La driver probably does it with presence--which itself is intended to be a way to see if the driver thinks the device is still online-but I'm not sure what, since forcing the "switch" attribute to be considered a state change would cause most subscribed apps to do something in response to that event, same as if it was just turned on after being off, which is definitely not what you'd want).
It would be helpful to link to this discussion since we are all guessing as to the real issue. 
Here is my best guess from searching: Generic Zigbee Outlet missing from RM (legacy) with Device Watchdog - #9 by bravenel. In that case, if you're using a custom app, you're at the mercy of however they're selecting devices, or you/someone could modify it as needed. But if you just want to run a refresh command every day or so, you can do that with Rule Machine, and you don't need the "Refresh" capability to do that. As long as the device has the command, which the built-in generic driver does, you can use a "Custom Action" in RM to just run the refresh() command (no parameters).
I might again revisit the particular device: do you have problems with it dropping off your network? I find apps like Device Watchdog useful for battery devices or known "problem devices" (like Xiaomi/Aqara devices), but with most powered devices, this doesn't seem to be an issue for me, and the utility of such an app is greatly diminished. A longer "activity" interval--with the generic driver and without any of the above--may be enough to help if you use this device on a regular basis. Otherwise, hopefully one of the above ideas will also work while solving your other issue (which itself is unclear to me since I don't use that app, but I'm assuming it's capable of ignoring specific devices or not using certain capabilities just because they're there?).
