This issue has been observed in CA PPM 15.2.
This issue has been reported to Engineering as DE37207.
This issue has been fixed in CA PPM 15.4.1.
The project can be opened in OWB after selecting all resources in the team tab, then choose the action "Set Allocation", then set "Default Allocation %" to "0" and check "Clear existing allocation segments", then Save.
Administration > Project Management > Settings
Staffing > Requisition Booking > "Use available work units" instead of “Use allocation percentage”
Implications of the setting above:
When using Allocation Percentage, a resource booked at 100 percent fully replaces another resource that is booked at 100 percent. The requisition is fully filled even if the hours they work each week are different. When using Available Work Units, if the new resource works fewer hours each week than the resource being replaced, the requisition is not fully filled.