The Bug
When doing /setblock ~ ~ ~ structure_block the clicking to open its UI the texture changes from data mode to save mode despite still being on data mode.

Replicate

• do /setblock ~ ~ ~ structure_block
• Open it's UI
  Notice that it's texture changes from data to save despite being on data

Notes

• Only works with /setblock ~ ~ ~ structure_block
• Pressing ESC doesn't fix the issue but pressing done does fix the issue