Probably there to cushion the bolt handle as it hits the action as the firing pin is released. That or to keep the bolt from closing more than necessary and having the cocking piece hit the ramp at the end of it's travel. If it works better with it, go with it.
On another brand of rifle I built up the slot in the action with some Devcon so the Bolt couldn't be closes to the point the cocking piece hit the edge of the radius and made the bolt close more when firing.
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