I recorded a multisport activity with several running and biking parts. It seems like the training load is cumulative, but gets counted for every part separately as well. The final run was only 0.35km and the load is 31.43km .
But this means that for the total activity (+- 22km running) it cumulatively counted all the training load numbers which ended up with a training load of over 250km. 
So now my watch thinks i had a huge training overload.
Screenshot of the final run piece: 