The bug
Even though beacons look almost like glass and you can see through them, the camera cannot pass through it in third person. Relates to MC-175866, MC-175927, MC-177512, MC-181095 and MC-189617.
How to reproduce:
Place a beacon in front of you of you and look at the beacon
Go into 3rd person
Move away from the beacon
❌ The beacon causes the camera to get closer to your body, even though can look through the glass.
Can confirm.