This bug report is a parity issue with Java.

Summary:

In the Java version, when lightning strikes a copper block (with any oxidation stage), the block oxidation state changes to any of the previous states (including the first). In bedrock, fullness does not alter block oxidation.

Works with any copper blocks (Slabs, Stairs, Blocks).

Steps to reproduce:

1. Place a copper block with any oxidation state (except for the zero, unoxidized block).
2. Wait for the thunderstorm.
3. Make the lightning hit the copper blocks (for example, using a lightning rod or using mobs and an enchanted trident...).

Observed results:

Nothing happened.

Expected results:

The oxidation state of the blocks will change (downward).

Video:

Java 2021-03-17 22-09-35.mp4