How long do Game Changers get early access for?

First- please do not speculate (nor give answers based on speculation).

I am aware that Game Changers can start doing videos on new content/ packs a couple weeks ahead of release, however, how far ahead of release are they given that access? And, are they able to play right up until release? I would like to know how long game changers get "early access" for,  and are we seeing (from them) the actual completed pack/s that they are doing the 'early access' for? Are the bugs (shown in their 'early access videos) fixed, before release?

*Edited for clarity.

I realize that there are bugs which come in the 'finished'/shipped game- however, I have seen the GCers making statements "I'm pretty sure this bug will be fixed before release" (and comments akin to that statement), and I don't think they should make those claims if it isn't true (which they have been doing). None of them are playing with their own packs integrated (to show the additional issues that come with adding a new pack), which is seriously problematic- as it is left to paying customers (who don't get the packs free- like the GCers do) to beta test, when it is supposed to be a fully developed and working product.

I've also noted that there is zero gameplay, and that the new sentiments and lifestyle systems are messing up gameplay (like sims emotions being all over the place, and affecting other sims emotions to be the same). There is also a lack of vivacity in the town centre (which is fine for me, but others who want that will not be happy). And, the world is 'beautiful, but empty' (as many game changers have stated).