This is similar to MC-174013 but may not be identical since not ALL new portals made in the Overworld are connecting to distant (or the first) pre-existing portals and failing to make new ones.  So far, we have made 4 portals.

#1 made in the Overworld (of course) at (-35, 81, 30) generated portal in Nether at (-18, 78, 5).

#2 made in the Nether at (-151, 77, 29) generated portal in the Overworld at (-1279, 85, 207).

#3 made in the Overworld at (8, 75, 2160) generated portal in the Nether at (-2, 82, 268). 

#4 made in the Overworld at (738, 81, 793) failed to generate a new portal and instead connected to portal #1.

Note that #4 SHOULD have generated a portal at (as close as it could get to) (92, 81, 99) (the Y coordinate being flexible, of course), which is 144 blocks (Euclidean distance) through the Nether from portal #1. The game should only be searching a 128-block radius for existing portals before making a new portal, so this is clearly out of range. 

Note that #3 correctly generated a new portal. Also #2, which was made in the Nether, correctly generated a new portal.

I will update with comments as/if we test further with more portals.