Losing Class References

Hello everyone, having a strange problem today that I think is a Unity bug (filed a report a couple weeks back but still no response despite having pro) and I am trying to find some work arounds for it.

Basically I am making a Custom Property Drawer and then linking that class to a manager. That works great, when I look at the managers array that references the class I can change the value whilst the inspector is in debug mode and see the value change on the source object (thus correctly linked).

However as soon as I make any code change and the editor recompiles the link is lost. The data is exactly the same in both places but now if I change any values the corresponding object doesnt update and thus their link has been lost. Its as though the previous refence has become a new instance of the object in itself which is really confusing!

Has anyone come across anything like this before?

Cheers! Jason