Could records in two parishes be explained if one of the spouses originated in one parish and the second spouse in the other parish? The marriage may have been held in one parish but recorded in the other as well. If so, there could have been one marriage in 1798 and another in 1810.
However, it does not seem likely that the same couple was involved in both. Why would they marry each other again after 12 years? The names William Rob(b) and Jean Meldrum are not unusual. In early nineteenth-century terms, it's a fairly long way from Fife to Dumbarton or the Gorbals.