I discovered this same issue in October of 2017 after upgrading from NPM 12.0.1 to 12.2, with the accompanying upgrade of NCM.
I opened a Support case with SW, they investigated it, and said this is a Cisco problem, and I should wait for Cisco to fix ASA versions.
My response was that it wasn't a problem for NPM 12.0.1, why is it an issue with 12.2. I did not receive a satisfactory answer.
As a result, my ASA 5525-X's show up as "Hardware Unknown" in NPM. Not a satisfactory state of affairs, and I'm hoping SW will work around this "Cisco issue" in a way that compares to how NPM discovered and worked with these ASA's back in 12.0.1.
Perhaps if you open a new case on the issue you'll discover a new solution or work around or hotfix. If you document your findings here, many may benefit from your experiences.
Interestingly enough, the 5525-Xs show up as ASAs in NPM, they just aren't recognized as ASAs in NCM when trying to download the config.
I'm running 9.8(2) for what it's worth and NPM 12.1
I've long had to avoid relying on NCM automatically recognizing ASA's and letting it choose the appropriate template. That behavior is documented in Solarwinds' technical support site.
I always manually choose the my template for NCM, which I tweaked to ensure NCM uses the "copy system:running-config" command when downloading the startup config.
I also had to tweak the "ignore" feature to not throw alerts when it sees the difference between running and startup configs for PSK's that show up unencrypted with the above command.
It works like a champ.