How does the reassignment count field work?
Release or Environment
Madrid, New York, Orlando
The count goes up when current assignment_group changes however, the current group is not set until after a record is inserted.
If you look at the audit history list for a record and add the column 'Update number' you can tell when the update was made.
Any change to assignment group with an update number > 0 will increase the reassignment count.
It is possible to see multiple group changes with an update number of 0 and they will still not count toward the reassignment count because the 'current' assignment group value is not set until the record is inserted.
Even if the record is created with a null value, any update to the group will increase the count. If a records assignment group is populated automatically as long as the update number is 0 it will not count. However, if the instance is slow the process used to update the group may change the group after insert intermittently and will show up as update number 1 instead of 0, which will increase the count.