In communist China, large organizations should be considered extensions of the government. Tencent is a massive media corporation, so they are likely working in lock-step with the CCP in regards to aggregation and dissemination of this information. They operate a messaging app with over a billion monthly active users. Their participation in all of this is extremely involved.

Even allowing that, why does it make sense for the government to hand them the very data they're trying to obscure? Unless you're arguing that they were somehow given the numbers in error, and then erroneously published.

It's probably Tencent doing the data collection/storage/management.

The Chinese government is going to outsource data collection and management of a disease epidemic to an internet software company, rather than their own ministry of health, who are actually trained and educated in healthcare work?