No, he wasn't absent. Werrason was always the main-act so he had always to step in as last singer, like JB Mpiana was doing in Wenge BCBG before Blaise Bula's departure.
Back in 1998, 1999 & 2000. It was always that Wenge Musica Maison Mere was starting the concert, then Adolphe making his entrace and singing with them and on the end Werrason making his entrance and singing alone with Maison Mere or sometimes along with Adolphe. In the mid of the concert there would always be a part of Adolphe singing 1 or 2 songs by himself with Maison Mere and then the rest of the concert continuing with Werrason and them ending the concert with the generique which was then number 1 (Ndombolo ya Solo before releasing Intervention Rapide, Intervention Rapide and later Solola Bien). There were some concert where they were Maison Mere was starting directly with Adolphe.