I've noticed this too.. specifically how it appears to me to operate (though I could be wrong) is that those who have uncustomized profiles as well as a particularly longtime membership in PC, seem to be the only folks where this is the case, which suggested to me that even if I returned all my profile customizations to a default setup, I likely still could not be grandfathered in to whatever earlier default profile seems to have solely allowed for not publicly showing the "you last visited" data.

Again, as this is an assessment made only from my own personal series of observations I certainly might be wrong; I would likewise welcome understanding for sure of what's possible in this regard -- especially since there is no feature to see how one's profile actually appears to others (outside of for the "about me" subsection only), making that a matter entirely of mystery.

I do use the invisibility "cloak", always have; it was one of the first things I looked for in settings here as it's always been my preference on social media not to have my activities be trackable. It's mostly out of consideration for others, that I don't want indications being made that I'm there and perhaps available for immediate communications when it may really not be the case, thus creating the potential for hurt feelings. (Also, I have an inherent aversion to feeling tracked in general... having had the experiences both of being stalked to the extent of legitimately having to fear for my life, and of being kidnapped and held against my will for an unfortunate length of time, I suppose it's a bit of a trigger for me personally.) But, at least as far as I'm able to tell, invisibility doesn't solely define the displaying of the "you last visited" data.