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i doubt there would be an option for this. The logic would be too difficult as not all numbers have the dashes in the same spot (i.e. international numbers)

Often times, the "old dumb phones" were unique to a region, i.e. North America, where the assumption of the phone number format was known. Android phones aren't region-specific so the same assumptions can't be made.It's a feature that's pretty common even in old dumb phones...
Presuming you use Google Contacts, export your contact list to CSV. Open the spreadsheet and tell the spreadsheet to replace "-" with "" in that column only. Save and import back into Google Contacts.I'm looking for a way to get rid of the dashes.
If you want to have NO dashes, select : Settings > Language and keyboard > Select Language > English (United Kingdom) or English (Philippines). To ADD dashes to phone number format : English (United States).