Definitely a coincidental foreign object in there, it needs to be removed. Carefully! I’d recommend removing the fuse before you start playing about.
Try pushing down on the edge of one side and see if it raises the other side, I’d try that technique at the opposite side to the small groove running down the barrel as that groove will give you a little more room to get underneath it if it lifts.
If that fails I would maybe try a drinking straw, place it onto the disc and form a seal and the suck, see if you can lift it that way. Or try some blue tack on the end of a straw and see if you can lift it out that way. If it stuck fast then try a Straw with a slit on either side at the end to splay the edges and use glue on the end to stick to the disc and pull it out once the glue has set. If it won’t come out then you can easily cut the straw.