Gantt bars problem

Dear friend,

I have some troubles with Planning activities in past dates. The first activity started in June, 5th, with 3 days of duration, the second started after, in June, 8th, with 10 days of duration, and the last will start in June 23th, with 3 days of duration. These activities have precedents, one another (except the first).

Initially, the bars was ok with their lenght and date position. But after changed task status to "attributed", giving to it a responsible, and after changing task progress planning to "regular between dates", my gantt task bars become unconfigured, even with correct planned dates. (see attached pictures)

How to I to do solve (or avoid) this problem? I need to register work allocation time, to show task and project progress by calculation, even creating a project with tasks with started past dates.

Please, someone has a suggestion?

Regards,

Hector Dufau