Erratic hearthlings behaviors when you have more than 20 of them

Summary:
Setting the population cap to 50, you start to observe erratic hearthlings behaviors if you reach the 25-30 cap. When some of them are working on a building site. They start something but suddenly stops. They bring useless objects on site. They are often iddle.

Steps to reproduce:

  1. Set pop cap to 30
  2. At 25-30 build large houses

Expected Results:
Usual hearthlings behavior

Actual Results:
Erratic hearthlings behavior

Notes:
none

Attachments:
none

Version Number and Mods in use:
Alpha 19

System Information:
AMD 64 8Go RAM