One was explained in the linked article:

"Amazon fired the warehouse worker Smalls on Monday, after he led a walkout of a number of employees at a Staten Island distribution warehouse. Amazon says he was fired for violating a company-imposed 14-day quarantine after he came into contact with an employee who tested positive for the coronavirus.

Smalls says the employee who tested positive came into contact with many other workers for longer periods of time before her test came back. He claims he was singled out after pleading with management to sanitize the warehouse and be more transparent about the number of workers who were sick."

In one case, an organizer was fired for refusing to not come to work after being put on "quarantine", three weeks after he was initially exposed and not given any leave, and no one else involved in the exposure was quarantined.

https://www.theguardian.com/us-news/2020/mar/31/amazon-strik...

The specific incidents Bray discussed seemed to be on a private internal list, and specifically related to AECJ so probably not this issue - I doubt anyone will leak it as unless there's something especially egregious (not just specious justification, but something like a racial or sexist slur) it doesn't really benefit either side.