Is there a bug when adding in the unused RRSP contribution limit? It appears to add it as a credit when it's really just unused space available to me to add to my RRSP.

There are two different spots in the RRSP section that may be switched. Your contribution limit is the amount of RRSP room you have accumulated (and it does increase year after year if you do not contribute). Then there's the Unused RRSP contributions spot. This is for contributions that you have made in years past but have decided not to use the deduction.

Check the Unused RRSP contributions section to ensure the RRSP contribution limit hasn't been entered by mistake.