Reproduction steps:
- Enter 123,456.78 into input field
- Select 123,|456|.78
- Drag |456| to beginning of input field
- Press CTRL + Z to undo
- Notice the input field is now 123.78
- Press CTRL + Z to undo again
- The field is now back to the original state 123,456.78
Interestingly, It seems like right clicking in the field and clicking undo (in Chrome at least) has the correct behaviour. However, using the keyboard undo shortcut puts the field into this in-between state.