Routing doesn't assign activities to some technicians

Summary:

Routing plan leaves some technians without activities multiple times.

Content (required):

Hi community we are testing some routing plans to assign three different activity types. Currently at one bucket(SE Metropolitina) we have 17 technicians:

• 9 with only the Work Skill A
• 6 with only Work Skill B
• 2 resources with all work skills (A, B and C).

All the resources are assigned to work zone associated to the bucket(SE Metropolitana), but when we run the routing plan the some several activities don't be assigned to technicians with the work skills required and keeps at bucket. 

For example, in the case below the routing plan didn't use 6 technicians when the others were full of work, so a lot of activities weren't assigned.