There is a bug in CSGO that allows to respawn outside of spawn. What is it all about?

The CSGO community is increasingly reporting a spawn bug outside of spawn.
Counter-Strike: Global Offensive players very often contact each other on social media or on Reddit. Recently, it can be observed that more and more people report a problem with some people spawning outside the spawn. Such a thing was previously due to cheaters, but now most people are betting on a bug in the game.
What exactly is this bug about and how does it show up in the game?
In the clip below, you can see evidence that some players can spawn outside of spawn. In this case, the whole situation takes place on Mirage, where one of the terrorists appears on mid at the very beginning of the round. This position gives him a considerable advantage over opponents who cannot expect him in there.

Most players assume that this time the cause is not external programs, but a simple game error. Interestingly, a similar situation was observed, for example, on Nuke during a short match:
At present, it is difficult to say with 100% certainty what is the cause of such incidents. However, Valve should become interested in the matter before more and more people start using this type of unfair play.