What makes carrot bits turn green in carrot pineapple bread? (And are they safe?)
Here is a super in-depth analysis of what may cause the carrot to turn green:

http://www.carrotmuseum.co.uk/turngreen.html

Unfortunately, it doesn't come to any hard conclusions. It does make it clear that it's not simply pH though, as a carrot will remain green even in a 0.1 M solution of sodium hydroxide.

It does provide an anecdote about a baker that had a similar issue, and how they solved it:


  [they overcame] it with a change in formula of baking powder and a good clean out of equipment.


Perhaps this could apply in your case? It might be a reaction from your cookware in combination with other factors? What if you remove the pineapple? Does it still happen? Perhaps trying a different brand of baking powder may work.

One thing is for sure, it's definitely not mold, and I'm very confident that it's harmless.