What happened to Kurama? So it's been a couple of years since Naruto ended, and I don't think the author answered this question/mystery within the Narutoverse: Isn't a Bijuu supposed to die after the host's death? How exactly did Minato have 50% left within him, and why did this chakra not return to Naruto?

If this was answered in some interview or solved, could you direct me to them? This could be counted as plotholes or something that was left to reader's discretion by Kishimoto-sensei.
When Minato used the Reaper Death (Dead Demon Consuming) Seal he essentially split Kurama into two parts:


Yang Kurama
Yin Kurama


Each half Kurama have their own conscience, making them two separate entities.


  Later, when Naruto and Minato bumped fists, Yin and Yang-Kurama came in contact with each other, with Yang-Kurama greeting its other half casually and asking it to share its chakra, which led Yin-Kurama to note that asking itself for chakra was an odd situation


The reason for separating the charka was because an infant would not be able to withstand the power of Kurama if he had contained both sides of his chakra.


  Since Kurama's chakra was too immense to be sealed within an infant like Naruto, Minato first used the Dead Demon Consuming Seal to separate and seal its Yin half within himself and then prepared the Eight Trigrams Seal to imprison the Yang half within Naruto


Furthermore, Minato, knowing the consequence of performing the Reaper Death (Dead Demon Consuming) Seal, seals Yin Kurama within himself.


  When Minato uses it, he seals only the Nine-Tails' yin chakra, leaving its yang chakra alone; this sealing of its yin chakra into himself makes him its jinchūriki.


The consequence? Death.... kind of.


  For a few moments afterwards the summoner can continue moving and speaking, allowing them to finish any lingering business they may have. Shortly afterwards the Shinigami will consume their soul and the soul of their target(s), ending their life. The souls of those trapped within the Shinigami's stomach cannot enter the Pure Land and are destined to fight with their victims for all eternity


With Kurama being split into two separate entities, one half was trapped within Minato while the other half lived on and was sealed within Naruto. Because the souls are trapped within the Shinigami's stomach, destined to fight each other, this also explains why Minato is able to use Nine Tails Chakra Mode.