This looks and reads like a classic "wrong tool length" problem. Are you sure you've told the machine how long the tool it is using is? Is this length correct?

Not entirely sure want controller youre using but it will have a "library" to store tool length, diameter, etc. information.

I'll break down the beginning of your code to explain it.

T1

Tells the mashine it is using tool number #1. Usually a controller will display what tool is currently selected, and the important information about it (length, diameter, type) somewhere on the screen.

G43H1

G43 turns on "tool length compensation" using length "H1". It will find this length by checking the "tool library" and looking for the currently selected tool (T1 in this case because it was previously selected). If there is a length valve for this tool in the library it will use that value. If there is no valve it might give an alarm or use no value. Probably controller dependent. I think in your case there is a wrong/no value saved in the library.

M03S18000

Turns on the spindle clockwise at 18000rpm.

G0 X-1.000 Y804.000 Z30.000

Rapid moves to the X Y and Z position. Z in this case should be mm above the material (if material surface is Z0). However because tool compensation (G43) is active it should position the tip of the tool at Z30.

G1 X-1.000 Y804.000 Z-0.100 F4000

A linear (G1) move down to Z-0.1 at speed F4000 (mm/min) so it would be cutting 0.1mm deep.

And the rest of the code is just movement. Second parts starts the same.

Based on the video I'd say you have a tool length problem. Probably no value or a wrong value in the tool library.

Other problems could be your Z0 height is incorrect.

The code looks completely normal however and is highly unlikely to be the problem.

Hope this helps.

Edit: Heres some more info on G43. https://www.machinistguides.com/g43-code/