This bug report is a parity issue with Java.

Summary:

In Java version, the beacon beam from 21w07a version ends at 1023 blocks from the source (beacon). In the bedrock version, the beacon is 70 blocks high from the source.

Steps to Reproduce:

1. Build a beacon.
2. Step on the beacon block.
3. Climb 71 blocks high.

Observed Results:

The beacon beam will disappear at block 71. (beam height 70 blocks from the source)

Expected results:

The beacon beam will disappear at block 1024. (beam height 1023 blocks from the source)

Video:

Java 2021-03-07 21-47-52.mp4