Earlier quoted context omitted.
Have read the whole article myself, I did not see that explicitly stated. Could you provide the quote?
> In addition, we identify potential areas of concern in Zoom’s infrastructure, including observing the transmission of meeting encryption keys through China.
FTA "We suspect that keys may be distributed through these servers. A company primarily catering to North American clients that sometimes distributes encryption keys through servers in China is potentially concerning, given that Zoom may be legally obligated to disclose these keys to authorities in China."
"We suspect" is not the same as "we are certain".