Hey there Unicomp!

Try my solution here. It happened to me too and what I found was this:

Even when I unreconciled/undid the reconciliation of everything from 2017. When I checked the bank register, there were transactions in the later years that were still "reconciled" status because they were matched to my Credit card transaction and my Credit Card was already reconciled. Those transactions created a wrong beginning balance which made me confused because at first I thought "The beginning balance of 2017 should be zero". I, then, removed the "R" status from those and my beginning balance went back to where it was supposed to be. 

You can try this and reconcile again. Long story short, there were ACTUALLY some reconciled transactions even though you thought there were none. And they threw your balance off. Just remove the R status and the problem will be fixed.