First thing, I'd look for are the presence of a return character inside an address field. This is the simplest way you can get a space between fields. To check on this, find the record where you see this extra space on a layout where you can edit the address fields and click into the address fields. Check both the field above and the field below the space you see.
In similar manner, check your records where you see the city name twice. I suspect that you'll find that an address field contains the city name in addition to the city name being entered into the city field. This may not be obvious until you click or tab into the field as a single line sized text field will only display the first line. If there are additional lines of text, clicking or tabbing into the field causes FileMaker to "pop out" the field and you'll see the rest of the data in the field.