Terramaster had some pretty gnarly security issues that they badly handled in the past. No big deal if you keep it walled off from the internet, but their software would never let you know it should be kept away from any internet access.
Also, if you get one of their units that has an ARM chip inside instead of an intel one, there is basically no chance you’re ever going to be able to use anything other than the software that they have by default. This makes the security issues impossible to resolve without completely removing internet access to the device.
It’s very much a thing. https://getcrankshaft.com/