Building Gadgets Version
1.3.8

Describe the bug
Using Building Gadgets as part of the ATM10 modpack. I am attempting to copy a structure from my creative test environment. When I first copied it, I did not realize that there were some scaffolding blocks still in place on the underside of the structure. I removed those blocks, and tried numerous things to get the Copy Paste Gadget to update what it had copied:

• Adjusted the size of the selection manually via the Settings menu (this showed the info pop up that x blocks had been copied after each adjustment, suggesting that it had worked)
• Manually reselected the region, and adjusted the height to encompass the full structure (structure narrows at the top, so cannot directly choose opposite corners of the needed 3D region)
• Using a completely new Template
• Using a completely new Template Manager
• Using a completely new Copy Paste Gadget
• Saved and exited out of the world, and reloaded

After numerous attempts at this process, the Template Manager now shows the phantom blocks in an area completely outside of the region that was selected, yet still in the rendered "copy".

Edit: It looks like this might actually be some sort of rendering error now. Looking at the materials list again, none of the phantom blocks that show up in the render appear in the materials list. During this process it was still showing those blocks as actual materials for a long time, but no longer, and I honestly do not know at which step that changed.

To Reproduce
Unsure which of this has led to the bug, but here is what I did:

• Create a large structure, such as a large roof, with extra blocks underneath the actual roof structure
• Use the Copy Paste Gadget to copy that area
• Place the Copy Paste Gadget and a Template into a Template Manager
• Save the selected region
• Observe the extra blocks are in the render and materials list
• Remove the Copy Paste Gadget from the Template Manager
• Remove the additional blocks that are within the selected area
• Use any method described above to try and force the Copy Paste Gadget to recapture the selected area
• Place the Copy Paste Gadget back into the Template Manager
• Attempt to save the selected region, either overwriting the existing Template, or by writing to a new Template

Expected behavior
Copy has updated and the blocks that were removed from the area are no longer part of the Copy as shown in the Template Manager

Screenshots

Log Files
Not experiencing any crashes, not using Rubidium

Confirmed that the rendering glitch is still there after pasting the selected area via the clipboard Copy/Paste options in the Template Manager.