'Invisible' status prevents booster pack eligibility - a bug or a feature?

[ᚺᛟᚾᛊᛁᛖᚷ]

I have noticed that setting your status to 'Invisible' (appear offline) (e.g. in Friends tab of the topmost menu of the Steam app) makes your profile page display you have not logged in since changing the setting to 'Invisible' and Steam uses that info (and not the actual logged times) to decide if you are eligible for booster packs of Steam Trading Cards for your games.

Thus if you remain 'Invisible' this way more than 7 days you lose booster pack eligibility - despite logging in with Steam app daily and Steam stating booster pack eligibility requires logging in at least once every 7 days not appearing online at least once every 7 days.

Is this intended (and just poorly explained) or is this a result of a mistake, a clash of two implemented features (when Steam card booster pack eligibility checks the last time online date assuming it is the same as the last time logged in date but at the same time 'Invisible' status is implemented which makes it so the last time (appearing) online is not always the same as the last time actually logged in)?

To clarify: I am only using Steam app, not accessing Steam via web browser (so it is not a web browser issue). I have tested what I am describing above - upon changing the status from 'Invisible' to 'Online' (and then back to 'Invisible') the account immediately becomes eligible for booster packs again - so it is indeed directly linked.

[cSg|mc-Hotsauce]

Probably intentional.