Mipmap levels no longer blend smoothly

Steps to Reproduce:

1. Disable View Bobbing to make the issue easier to observe;
2. Find the "line" created by the mipmap threshold;
3. Walk.

Observed Results:
As soon as the block enters a certain range, details just pop in. This issue is not as noticeable on smaller screens, but it's still there.

Expected Results:
The different mipmap levels get blended together, making the details appear smoothly with no hard cut-off line.

Screenshots/Videos attached: Yes

Notes: