New Start Date setting paid invoices as not paid from previous year

I am currently on Manager 18.11.37 (windows 10 version)
I have invoices from a previous year which are all showing is paid invoices in status column. (in the if the start balances date is 6 Feb, 2017 (start of my company). All Invoices were paid in 2017.

If I reset the Start balances date to 1 Jan 2018, the invoices for 2017 now show unpaid. In the starting balances screen after the date change shows an outstanding balance for invoices which should be 0 (as they were paid in 2017 and with the original start balances date show paid).

I can put in available credit equal to the amount shown as unpaid but that seems that I should not have to do that. (I also do not know what other things are affected by this action).

What do I need to do correct this error?

Why are you resetting the Start balances date?

The Start Date is only used when transferring accounts from another system. I t indicates the date that you start entering accounting entries in Manager. It has nothing to do with the start of your financial year.

Read the guide Close an accounting year

Also read the Guide about starting balances.

Your situation may also be related to automatic allocation of receipts to invoices. Read the Guide about that, too.

Thank you Joe, I miss understood its usage.