I'm trying to figure out a wierd problem, maybe yous guys can help.

I'm deploying a web part using powershell (Update-SPSolution) in a build definition.

The deploy works, but every time one application pool is stopped, and to make this more wierd this web app does not use the web part.

I've been reading the logs trying to find something to sugest a problem, but I cant find anything useful. 

Unlike this [question](https://sharepoint.stackexchange.com/questions/4728/update-spsolution-stops-application-pools-on-iis) my web part is in one single project and it deploys "quickly" (~ 1min)

Thanks for any insight

**UPDATE**: I've manage to find a workaround, defining the solution setting "Reset Web Server Mode on Update" to Recycle.

But I'm still troubled on why the problem exists in the first place, and if it's allways going to append on each new solution.