I have a similar watch. From memory, there is an attachment on the watch case onto which the (gold) centre tube slides, a pin then slides through that to fix the two end bits. It looks like the attachment has come off the watch case and someone has tried glue to fix the centre piece back on...which probably won't work.
It may be possible to get someone, with skill, to laser weld it perhaps? Either that or a new watch case (not cheap).
The bracelet designs on these Constellations are trouble. I've had pins sliding out then getting bent and clasp issues. Omega quote for a new bracelet, £425...way more than my watch is worth. Sadly.