Real work recorded on Pool

Dear,

Into real work report, I get as expected some real work recorded for ressources assigned on the planning. But there is also some real work recorded for a pool containing these same ressources. That real work seems corresponding to 100% of the work validated on corresponding activities assigned. That pool has been initialy created and assigned to all activites of the project, that people can access and record real work without being nominally assigned and planned on all activities.

Only ressources record individually some real work through their timesheets. I shouldn't find some real work recorded in front of that pool. How a pool can record automatically some real work? How can I delete that real work?

Regards,