Cannot use a water bucket to right-click a furnace

[MissingProMC1]

In MCP, when holding a water bucket, right-clicking a furnace does not do anything.

It can be done with a furnace.

Just craft a bucket, get some water, run /furnace and then try to open the furnace menu while holding the water bucket.

I am using version 1.20.6, on Java Edition.

If you want footage of it, I'll be happy to give some to you.