The way that front end is set up looks deadly, and not in any good way. There is something seriously wrong there. The linkage arms should be close to the same length and approximately parallel, not at sharp angles to each other. The way that is set up your trail is going to change radically as the suspension moves, which isn't good for handling. Even BAD trail is somewhat manageable, as long as it isn't changing all the time. It looks to me like the hammer plates (the upper and lower trees at the neck) are a lot farther apart than the pivot points on the girder. Maybe it was built for a bike with a shorter neck and then modified to bolt onto this one?
The girder hitting and bending the spring back is a result of this issue, not the main issue.