582 exhaust to manifold seal

Here is the video of the amount of smoke. It started fine but the amount increased as the engine kept running...

Rotax 582 start

Just learned that Rotax switched from 2 piece exhaust to 3 piece. I have a 2 parts (the pipe attaches directly to manifold). Can this be the reason for a bad seal? Should I switch to 3 parts (cutting the 90 degree from the pipe and welding a female balljoint and getting a 90 elbow)?

Your picture and video do not offer up much information. No part of the installation was visible. Two things I noticed are; there was no movement in the exhaust outlet which tells me that it is probably mounted to the chassis in some manner. If the engine is on flexible mounts the spring loaded ball connection will leak. The amount of smoke indicates an incorrect fuel/oil mixture. Drain the fuel and start over with the correct mix.