[1.16.5] RFTools Builder preview mode is showing wrong preview blocks then leaving them as ghost blocks

[Peca21]

If you place a builder with a shape card inside and activate preview mode, extra preview blocks will appear. And when you disable preview mode those extra blocks will stay as ghost blocks. Right-clicking them removes only one block as well as mining. BUT reloading the world removes them.
Video: https://streamable.com/j4d4s7
Java 1.8.0_242
Forge 1.16.5 36.2.22
mcjtylib-1.16-5.1.2

[MushuPlatypus]

If I put in a shape card and set dims to: 41 140 41 and offset to 0 0 0 and then click the preview button, the offset is moved to 20 70 -21. I've put the builder at y 0.