Recurrences are not separate items.  A recurring item, no matter how many
you seem to have it on the calendar and how many of them have been modified
for a single occurrence, is only one item in the calendar.  By changing the
series, putting in an end date, for example, you're asking Outlook to
rewrite that single item.  It does, recalulating all of the individual dates
based on that new one item.  Outlook didn't decide to "re-make history", you
did by changing the original item.  In the process, the exceptions you may
have created along the way are lost because everything gets recalculated.
If you don't want that to happen, don't make exceptions to a recurring item.
Create a new item reflecting the unique values you need.

The functionality of a recurring item is in the fact that a single entry can
show up many times on the calendar so you don't have to enter all the dates
individually, not that you can store exceptions in it.