RTFA. Nothing was debunked. WaPo say very clearly:
At the time, Zuckerberg told remaining employees the company had made a substantial cut to “minimize the chance of having to do broad layoffs like this for the foreseeable future,” according to a recording of the companywide meeting reviewed by The Washington Post.
WaPo also says very clearly he delivered a different message to investors.
The tweet from that meta functionary weasels around this.