Hi Denis,
For automatic matching to occur, you should use the Import > From Bank feature. Import from another app is designed to use for the case when you have data in another application that you want to move into Savings. In such cases, the assumption is those transactions are not already in Savings, so no existing transaction is modified.
The matching behavior is essentially reconciling your manually entered transactions with those coming from your bank, so it only makes sense for import from bank.
Does that make sense?
Yi