When Harry, Hermione, and Ron leave Shell Cottage in Deathly Hallows we are told that they needed to leave the bounds of the Fidelius Charm in order to Apparate:
All three of them glanced back at Shell Cottage, lying dark and silent under the fading stars, then turned and began to walk toward the point, just beyond the boundary wall, where the Fidelius Charm stopped working and they would be able to Disapparate.
Likewise, this answer argues that Lily was unable to escape Voldemort via Apparition because it was blocked by the Fidelius Charm.
However, earlier in Deathly Hallows when they escape from the Ministry, Yaxley grabs onto Hermione and arrives with them at the front door of Grimmauld Place. When Hermione explains this to Harry, she expressly states that she brought Yaxley within the protection of the Fidelius Charm:
"Harry, I think he can. I — I forced him to let go with a Revulsion Jinx, but I'd already taken him inside the Fidelius Charm's protection. Since Dumbledore died, we're Secret-Keepers, so I've given him the secret, haven't I?"
This indicates that they had Appareted into the Fidelius Charm's protection.
Similarly, when Lupin visited them in Grimmauld Place he states that he had to Apparate precisely onto the front step to avoid being seen by the Death Eaters outside:
"I had to Apparate very precisely onto the top step outside the front door to be sure that they would not see me.
The implication here is that they would not be able to see him because the front step was included in the protection of the Fidelius Charm. But that would then mean that he was able to Apparate into the Fidelius Charm.
So which is it? Does the Fidelius Charm prevent Apparition or not?