Shishupal Jarasangh

I am confused currently about the Rukmini Haran track

Here Jarasangh is behaving like the father of Shishupal. Rukmi says that after marriage, Rukmini will become the Maharani of Mahadh Samrajya

Balram says that Rukmi aur Jarasangh ki Magadh Sena, Chhedi ki sena sab virudhh hai

I am completely confused, firstly I don't think Jarasangh ever took Shishupal as his son, he was just as any other vassal king to Jarasangh maybe was one of the most loyal ones, secondly even if we take it that he considered Shishupal as his son, still there is no reason why Shishupal's wife would become Magadh's queen. 

Is it a blooper? But it's like been shown multiple times. Are they confused about Jarasangh Shishupal relation? Can't accept this from Ramanand Sagar ji

What do you think?

Won't comment on the Sagars anymore, but here's the original story

• When Sishupala was born, he was born w/ 4 arms and a third eye, and was pretty terrifying.  An akashvani (similar to Kansa's) announced that those 2 extra arms and the extra eye would disappear when he was taken in the lap of the person destined to kill him
• When Krishna was an youth (probably after he had returned from Sandeepan's ashram and during the early wars w/ Jarasandha), he visited Chedi, and took Sishupala on his lap and those extras disappeared.  Shrutashrava - Sishupala's mother - then begged him to show mercy  on Sishupala, so Krishna promised her  that he'd give Sishupala 100 chances
• Damaghosha - Sishupala's father - was concerned about this destiny, so he turned Sishupala over to Jarasandha as a mentee.  So somewhere in the latter wars of Jarasandha, Sishupala started taking part (the serial shows Sishupala as fully grown and much older than Krishna on the eve of the first war, but that couldn't have been, since Krishna was a youth when Sishupala was an infant)
• So Sishupala participated on Jarasandha's side until war #17, and war #18 was Rukmini haran, where Jarasandha and Sishupala were defeated by Balarama and Rukmi by Krishna
• Sometime after the war, Damaghosha died and Sishupala succeeded him to the throne of Chedi
• After Jarasandha was killed by Bhima, Sishupala decided to align w/ Bhima when he covered Chedi during his Rajasuya visits, hoping probably to win Pandava support against Krishna.  So he found it grating when Krishna was given the honorary role at the yagna, and that's where they had their final confrontation
  

In SB, when the Pandavas were settled in Indraprastha, there was one family reunion occasion when the Yadavas came to Vrindavan, and Damaghosha was mentioned as one of the attendees.  So Sishupala became the king of Chedi sometime after the Pandavas became the rulers of Indraprastha, but sometime before the Rajasuya yagna.

P.S.  It's Jarasandha, not Jarasangh.  Sandha means 'putting together', and Jara is the name of the rakshashi who put the 2 halves of Jarasandha together

I know the original story. I just want to ask why are giving a look like Shishupal is the son of Jarasandh(thanks for correcting me)

I think they misinterpreted the relationship b/w Jarasandha and Sishupala.  Damaghosa sent Sishupala to Jarasandha as a mentee, which also bought Chedi the tacic backing of Magadha against any other powers that might wish to subdue them.  RS took that to mean that Sishupala became Jarasandha's adopted son in the same way Pritha became the daughter of Kuntibhoj.

But even RS showed Jarasandha being succeeded by his son, and Sishupala being nowhere in the scene.  Pretty strange for a son, if you ask me?