When right clicking on certain tinkers blocks which are not usable at the time of right clicking, the hand animation is still played, despite the fact no interaction actually took place.

As Mojang have been cracking down on cases of these in vanilla in 1.15 and 1.16, I'd also recommend removing these from the mod as well where they arise.

Examples:

• Seared faucet
• Casting table
• Casing basin
• Melter, with a bucket, when an insufficient amount of liquid is inside

• Minecraft: 1.16.5
• Forge: 36.1.0
• Mantle: 1.6.92
• Tinkers Construct: 3.0.2.96

Confirmed

Can it be reproduced with just Tinkers Construct? If not, list the other mods required to reproduce the issue.
Almost certaintly

A lot of these happen in the mod because we handle 90% of interactions on the serverside, but the client side is responsible for reporting if the arm swings. In those cases its a pain to detect that the interaction cannot happen.

In the remaining 10% of cases, we just wanted to ensure you don't accidently use your lava bucket when wanting to fill a tank just because the tank is full. There is a way to swing the arm less for those, but low priority.

Overall, going to change this to enhancement instead of bug as nothing is broken, its a minor visual thing.