Dates on downloaded transactions overwrite previously entered dates
When downloading transactions from your bank, you might be either downloading new transactions, which have never before been entered into Microsoft Money, or downloading transactions which you already have manually entered.
When downloading transactions which will match previously entered entries in the account register, Microsoft Money will either use the downloaded date, or the existing transaction date.
By default, the option is to use the bank's date. This may not be suitable.
If you want to change the download to use your date (or back to be the bank's date), then toggle the option in Tools->Settings->Online Services which is labelled 'Overwrite transaction dates with dates from downloaded transactions'