There is a degree of incompatibility between employee ownership and how we think about equity in traditional companies. This isn't to say that selling the company needs to be impossible, but it may only be possible with collective decision making rather than individual shares being easy to buy and sell as they are on a public stock exchange.
The problem I see with Huawei in this case is less to do with being able to treat your ownership share as an easily fungible asset and more to do with the fact that it appears the employees do not have effective control over the company. i.e. they don't get a say in who's on the board, financing decisions or anything like that. If employees through a fair, democratic system effectively have sovereignty over what the company does (and there's no one with a massive ownership stake to veto them hanging around) then you have some semblance of legitimate employee ownership.
The buy-back mechanism isn't great either, if that is how you want it to work then it should be based off of a fair and independent valuation of the company which it appears that it isn't.
I also think it's unlikely that an employee owned company could have the kind of control over the company that it should have when it's operating from a literal dictatorship.
And you know, even this is all assuming that this article is accurate and not just a FUD think-piece to support the American government's stance on the company, having not really done a great deal of independent research on Huawei myself.