Dorcas Spencer (Gardiner) - There are a lot of Dorcas Gardiners in Rhode Island!

Dorcas Gardiner, wife of James Clarke
Dorcas Gardiner, wife of Henry Tanner
Dorcas Gardiner, wife of Silas Spencer
maybe Dorcas Gardiner, wife of Nicholas Bates

Dorcas Gardiner, wife of Henry Tanner, had only one husband. Her husband outlived her and re-married.
Dorcas Gardiner Clarke had children 1761-1769, good sources for them
Dorcas Gardiner Spencer had children started in 1759.

There are trees that have Dorcas Gardiner married to both James Clarke and Silas Spencer but given the children above, that doesn't make sense.

There are trees that have Silas BATES married to Dorcas Cordiner with a son Nicholas Bates. Is this garble or just coincidence?