The CLA can never override the code license. It handles the transition of your code into their code, and what they can do with it. But once it's published as AGPL, you or anyone else can fork it and work with it as AGPL anyway. The CLA can allow them to change the license to something different. But the AGPL published code remains published and usable under AGPL.
I'm usually fine with contributing under CLA. A CLA often make sense. Because the alternative is a hassle and lock-in to current constructs. Which can have its own set of disadvantages.
A FOSS license and CLA combination can offer reasonable good to both parties: You can be sure your contribution is published as FOSS, and they know they can continue to maintain the project with some autonomy and choices. (Choices can be better or worse for others, of course.)

"early stages", "could not verify", "company did not respond", "considers making available for purchase"
That's neither solid news, nor a real or full GitHub alternative.