The bug
Despite the hitbox being small enough, buttons, levers, variety of torches, and tripwire hooks on the side of a piston will break when the piston extends.
Related issues
is duplicated by
Attachments
Comments

This 'bug' (if it is a bug in the first place) is very useful actually, since you can power the piston with a 0 tick signal this way.

I believe this is because when a piston is powered, the base block is switched for one without the "head" and this couldn't be changed without a complete re-code of the piston.

Affects 1.16-rc1, i want to request ownership to update the ticket 🙂
Since the ticket is not that old (created March 2020), you can't request ownership without @unknown's consent.

This also affects Torches, Redstone Torches & Soul Torches
Can confirm in 20w48a.

Can I have ownership of this ticket?

Confirmed for snapshot 20w49a

Still an issue in snapshot 20W51A

Still an issue in snapshot 21w03a

This is still an issue in 21w05b

Can confirm in 1.17 and 1.17.1 Pre-release 1.

Can confirm in 1.17.1.
Can confirm in 1.18.2 and 22w15a.
Can confirm in 1.19.
Can confirm in 1.19.2 and 22w42a.

I can also confirm exists in 1.19.2

@Kranberri attached blocks don't break when on the back of the piston, so I don't think that would be necessary

Buttons and levers also break when on the top or bottom side of a horizontal piston. Torches break when on the vertical sides of a piston, like buttons, levers, and hooks, but do not break when on the top side of a piston.

This is a parity issue, in Bedrock Edition they will not break when extended.