Oh my. Then I wonder where did you pull that definition from. Your ass?
But to your credit you managed to pull something. Let's discuss that source then. I'll be generous and just discuss that specific source and not cross-check it with other definitions by other experts or literatures. I'll even ignore the newer version of that glossary. Let's see.
Now for context, let's pull the definition of alpha testing first, because to quote you, "Alpha testing should already have validated the software, i.e. it should be more or less bug-free when it reaches Beta stage."
See, the difference between alpha and beta lies in the site of the test and the population (which checks out with one of my previous posts), and has no specifics on whether or not the product should be "bug-free when it reaches beta stage." It actually refers to the same thing, acceptance testing, which we will discuss after dissecting this definition.
"Whether or not the system satisfies the user needs and fits the business process." Now let's take an example of the bug mentioned in the OP. Inability to give commands after battle. Does that satisfy the user needs? Nope. Neither would crashes and other bugs or errors. I'll refer to "Functional Suitability" from ISO 25010 for this particular quality. A bug or error violates the sub-characteristic "Functional Correctness" of "Functional Suitability". Now let's look back at the glossary. According to the definition of beta testing, it is where we handle this, so you're wrong.
Now let's move on to acceptance testing. Again, referring to the very same glossary you mentioned, let's look at the definition.
Pretty much the same thing except for the mention of acceptance criteria, which is defined as:
Now, where is the part which says that finding bugs and fixing them is not part of beta testing? Try to be polite this time. Save yourself the embarrassment.
Edit: It's 1AM where I live, so take your time pulling whatever you want to pull. I'm going to sleep.
In all fairness, here is what I could get from a quick research :
The first uses of the term beta can be traced back to IBM in the 1950s. According to Allan Scherr (a former IBM employee), the terminology originated during his time there. They referred to testing product ideas and theories as “A” testing and testing feature complete products as “B” testing. Over time, the “A” and “B” became “alpha” and “beta”, creating the terminology that we commonly use to this day. Since IBM was the gold standard at the time for business processes, more and more companies started to catch on to the idea of A and B testing, and thus, alpha and beta testing were born.
I think you guys might give him a point here instead of trying to save one's face on arguing.