There is a bug which requires Overworld/Nether Portals to be at the same Y coordinate to link correctly, in the Bedrock 1.16.0 update.

After creating a portal in both the Overworld and Nether (at the correct X/Z coordinates so they should link), then entering the Nether, I am transported to a Y coordinate that is BELOW the portal I built in the Nether. This completely breaks Nether Portal linking in the new 1.16.0 Bedrock version and this was a reported bug in the Java version of one of the 1.16 snapshots.

Portal Coordinates;
My overworld portal is located at: 1040, 65, 368
My Nether portal is located at: 130, 94, 46

Expected Result:
I should appear at: 130, 94, 46

Actual Result:
I appear at: 130, 70, 46

As you see above, my Overworld Y Coordinate is 65 and my Nether Y coordinate is 94.

When I enter the portal in the overworld, it places me at: 130, 70, 46
(X/Z are correct, but the Y is wrong. It places me 23 blocks directly below my portal - at the wrong Y coordinate)

Conclusion:
This is actually not a bug/issue - this was related to using MCCToolChest to reset the Nether. Please read my comment below for further information.

Mojang - please ignore/close this.