Someone asked me to look into this bug. You are correct. But it will only happen on some days.
For those of you who cannot get the necklace:
See below on how to enable console, then:
Follow the guides through-out but remember there is a bug during the sunbathing scene. You must enable console, enter: dameba=2<PRESS ENTER> enter: exit<PRESS ENTER>, then try sunbathing. Keep setting dameba=2 if it doesn't work for you when sunbathing. The dameba variable is always set +=1 from sunbathing but the scene from which the necklace check can happen is <random (well, day)> and only triggers if dameba=2. Not sure how the author missed this...(money of course...)
SHE MUST BE IN YELLOW SWIMSUIT. KEEP TRYING UNTIL STORY CHANGES. Then don't modify dameba anymore but continue your visits to YELLOW SWIMSUIT (do not touch dameba anymore...). Eventually you'll need to use Stronger Pills in the bathroom until she tries to change the scene. Then go BACK TO YELLOW SWIMSUIT until she H!-scenes you.
I figured I'd keep the console simple for people.
If you can't figure out how to enable console:
Edit .\renpy\common\00console.rpy, search-and-replace config.console = False to config.console = True, save.
Delete .\renpy\common\00console.rpyc, notice the rpyc extension. This will force the game to recompile and cache the python script.
(Obviously do this with the game not running...)
Shift+O (Not Zero) to activate console in game. I do not recommend you tamper with anything but what I mentioned.
Uploaders should probably unpack the RPAs and patch bug, re-upload as unpacked. Should shrink game size considerably seeing as RPAs are terribly compressed. This would also allow people to more-easily fix bugs by providing RPYs to drag and drop for the gimmies and less literate.
Also: People with Renpy games...stop telling people there is a "saves" folder in the directories of Renpy games. It is a HARDLINK, not a FOLDER. They function similarly but the HARDLINK aka SYMLINK (not a SHORTCUT but like one, the HARDLINK will function like a shortcut but is seen as a legit folder to software that doesn't bother to go out of its way to determine if it is a HARDLINK) points to %UserProfile%\AppData\Roaming\GAME... This is why Renpy games can be deleted but your saves aren't bothered. When you 'copy' the HARDLINK folder, you're not actually copying a folder, though when you paste you'll be making one. Don't bother doing that because if you ever forget to replace that folder, Renpy will automatically HARDLINK as it usually does and you'll then be using old saves. *grumble*
Its really a pain in the ass to play it without a walkthrough mod, the game mod have a walkthrough but there are just scenes of the mother 
