Updated as of 30 / 04 / 2021
Summary
When you're scraping or waxing copper blocks, the particle doesn't appear. This only happens in the world without enabling Caves & Cliffs experiments toggle.

Step to Reproduce
1. Create a new world, don't enable any experiments toggle
2. Place down waxed and oxidized copper blocks
3. Try scrape it
---> No particle appears.
4. Place down normal copper blocks.
5. Wax it.
---> No particle appears either.

Original Description
particles disappear
I play on the split screen, when I put the wax on the copper block, or when lightning strikes the copper block, the particles do not appear.