I’d like to know what it is exactly about and what is peoples issue with it.

in short,it was meaning that ferre was the last member of wenge 4X4,then as he missed wenge reunion concert and heritier came werra gave that name to heritier,and heritier rubbed it in people's  face especially ferre who he always keeps tendency to go to beef with always thinking about how he was used to unsettle ferre from 2002 to 2004,then the ferre camp reacted,and the waffle just went on for weeks  until heritier brought back videos of werra calling him like that while in maison mere in 2001 2002,while clearly knowing that all happened around 4X4 concert
then ferre recently reacted as "okay just let him have that name anyways of last children of wenge 4X4" 

The problem with Heritier unlike Ferre, Fally (to someeee extend Fabregas), he can’t survive on his own, he always needs the backing of Werra and Jb. Think about it he spent 14 years in Maison Mère, and spent 5 years without Werra but still has Jb’s support like he still needed him to help defend against Maison Mère, he’s like that child that can’t move out of his parents home fully, he’ll buy his own property but will still go and sleep at his parents or uncles house. 

And I think that Heritier actually buys Werrason's support going by the way Werra himself justified having him on the stage instead of other old ex Maison Mere members. If he stops sending those Airtel Moneys that Mama Mampata shouldn't know about, the relationship won't be as strong as it currently is.

Thank you. For me it’s seems to make sense that Ferre would be the last son of Wenge 4x4 and Heritier would be the last son on Wenge MM.