Birthday: "Show age in profile" option hides Day & Month

Hello.
1) Turn ON "Show age in profile" option in backend
2) Navigate to "About me" profile page.
Result1: Page display "07 Feb 1979 (40 years old)".
3) Navigate to "Timeline" page.
Result2: it display only "40" and cake icons. Looks like "40 cakes"

Is it designed like that or a bug?

I expected that "Show age in profile" should ADD age "(40 years old)" like in Result1 to to avoid for users to make calculation by user themself, but not REPLACE it.

It's useless to replace Birthday by Age in "Timeline" at the moment, because I can see full Birthday in "About" page anyway. So it doesn't hide Day & Month.

I suppose the only data user can hide is:
1) hide only year (and age, as result)
2) or hide full Birthday (hide year & age).

So I suggest to display on both page (Timeline and About) the same date:
1) "07 Feb 1979" if "Show age in profile" option disabled
2) "07 Feb 1979 (40 years old)" if "Show age in profile" option enabled
3) "07 Feb" if user hides his year/age only
4) nothing if user hides his full bithday by private settings.
=> make Day and Month always visible (if private sittings allow it)

May be I wrong, but I think it worked this way in some ES 2.x version?

I just check VK.com social network (screen attached) - it works this way (user can hide year or full bithday, but Day and Month always visible). It allow to set up pricasy:
1) Show my birthday
2) Show only month and day
3) Do not show my birthday

Usualy people waths to hide they age. I don't know people who wants to hide Day & Month, but show age only.

Can you please discuss this case?

Thanks.