Point in Time Headcount with Salary report - isolated doubling of salary

Summary

Our "point in time" report is mostly working. For a very small percentage, the salary amount is being doubled

Content

We have a report that is working fairly well.  It is a point in time report against Compensation - Salary History Details Real Time and Workforce Management - Worker Assignment Real Time. It is pulling assignment details and the salary as of the prompt date and will include people that are now terminated (if they were active as of the prompt date).  

For 7 employees (out of roughly 1400), the salary amount displayed in the report is being doubled when we run the report as of 12/31/17. When we run it as of current date, the salary appears correctly for those employees.  I haven't been able to figure out why it's doubling for such a small population as of that past date.