When the world has addons, beacon effects stop when entering the chunk that includes the corners of the square radius of the beacon effect.

Adding a ticking area that includes the beacon within the intended affect area restores the full radius of effect.

Steps to Reproduce:

1. Create a new survival world.
2. On Advanced, set Show coordinates to On.
3. On Cheats, set Daylight cycle to Always Day. Set Weather cycle to Off. (These are almost certainly unneeded.)
4. On Behavior packs, activate either Markers Pack or DragonFire Lite Add-On. (I tested a world with each, and bug appeared.)
5. Click Create.
6. When world loads, set gamemode to creative so you can work in peace.
7. Give yourself some gold blocks, some beacons, and some iron ingots.
8. Move to 7, 7 at any Y and make a tall column of gold blocks so you can easily see where the center of the chunk is.
9. Move to 57, 57 at an equivalent Y level. Build a 4 layer beacon out of your gold blocks with 57, 57 as the center.
10. Place the beacon on top. Choose any effects, and activate the beacon with an iron ingot.
11. Fly back toward your gold pillar. 
12. Stop at 16, 16 and check that you still have beacon effects affecting you, and that they refresh.
13. Step forward to 15, 15. The beacon effects are no longer refreshing, and will fade away.
14. Set a ticking area circle with a radius of 4 so that it includes the beacon: /tickingarea add circle 0 0 0 4 home
15. See your beacon effects resume affecting you.

Observed Results:
Beacon effects stop when entering the chunk that includes the corners of the square radius of the beacon effect.

Expected Results:
Beacon effects affect the player throughout the entirety of their radius. Beacons should work correctly regardless of whether or not addons are being loaded.

Notes:

I tested this with two dissimilar addons from the marketplace, loading only one per test world to see if it was all addons or just particular ones: Markers Pack and DragonFire Lite Add-on.

I only realized ticking area affects it because I originally found this issue when I removed a ticking area I had created to deal with the minecart stoppage bug.