The 1846 marriage has no other details on the Maughold par register - extra details were added from 1849 onwards.

2nd John & Margaret:
6 Aug 1850 John CORKILL Full age Bachelor Farmer Ballagorey moar, [father] John Corkill, Farmer, and
Margaret KERMODE Full age Spinster Ramsey, [father] John Kermode, Farmer.

This second John Corkill was the heir of Ballagorry Mooar (farm) and died in Maughold in 1881 - will: estate Ballagorry Mooar in trust for son and heir John after wife Margt’s death – she predeceased him.

So your records look correct for the first John & Margaret marriage.

Sue