Lumen creating light areas where it shouldn't

Hi,

Workflow : Model Sketchup Pro -> Export to udatasmith -> TM

First issue : The model materials seems to have lost their scales (i have to put 100 in the scale of TM material for it to look decent.

Second issue : In real time render using Lumen, these artifacts are appearing

Third issue : When rendering this detailess view, it took 80sec to render with Lumen versus 4sec with Path tracing.

Thank's in advance,