How does China square its doctrine of “non-interference in internal affairs” with tacit support for Russia's invasion of Ukraine?

China has a long-standing policy of (at least publicly) not interfering in other countries internal affairs, and condemning any other country's 'interference' (read criticism) in its own 'internal' affairs (including Xinjiang, Hong Kong, etc).

China recognises Ukraine as a sovereign nation, with Kiev as its capital, and the two countries have diplomatic relations. So Ukrainian territory cannot be considered internal to Russia.

However, when it came to a vote in the UN Security Council on a resolution condemning the Russian actions in Ukraine, they abstained.

So in this scenario, when Russia clearly interfered in Ukraine's internal affairs (by a full-scale invasion), it is suddenly ok.

How do they justify these two apparently contradictory positions?