[NEEDS INPUT] Random teen body shape changes

Product: The Sims 4
Platform:PC
Which language are you playing the game in? Русский язык
How often does the bug occur? Often (50% - 99%)
What expansions, game packs, and stuff packs do you have installed? All to the date
Steps: How can we find the bug ourselves? Create a vampire from a teen (other age groups may also work) or make a teen vampire (not vampire may also work) to grow up
What happens when the bug occurs? The body shape of a grown sim or/and vampire alternate form randomly changes, not a weight or muscle mass - a SHAPE.
What do you expect to see? The body shape must stay constant!
Have you installed any customization with the game, e.g. Custom Content or Mods? Not now. I've removed them.
Did this issue appear after a specific patch or change you made to your system? Neutral/Not Sure 

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Recently I have noticed that the body shape of a vampire alternate form (dark form) was different from that of original form. it wasn't a big deal, because 1) you can copy the look of original form to alternate form without cheats or mods or any big efforts; 2) it's an ALTERNATE form after all, it can be explained gameplay-wise.

But then I've played with this teen-vampire longer and when she became young adult I've noticed her ORIGINAL body (and ears) were also changed! Here are the screens (it's a female just because you can better see this on females, nothing more):

BEFORE AFTER 

This Sim was fully created by game, I haven't make any customizations to it. I have only made her dark form look like original after I've found out it differs. Now, the dark form looks like it should, and the original form is altered! 

Of course some will say people changes with aging. My friends, women breasts don't grow smaller, naturally, I mean. THAT smaller at least. ALSO take a look to the EARS. Wow, that's not explainable at all.