It's the snap setting. Snap and Cursor snap is on, but for some reason, no grid is selected. This basically causes everything to snap to 0,0 and nowhere else.

Right click the snap button in the lower right, and click on one of the existing snap grids in the list (or create a new one)

The change doesn't change anything in the actual map, just changes some parameters for how CC3+ does the rendering of it.

The setting is persistent in CC3+ until you close and reopen the program, so it will affect any maps you open in that instance of CC3+.

To always have it load for a particular map, you can put DELAYDRAWSYM 0 into the OnOpenMacro of the map file. (Obviously, this will keep it active for the lifetime of the instance and not just for that map)

What is happening here is that when effects are on, that background picture, which also resides on the floors sheet (it probably shouldn't bee on this sheet though), gets re-drawn on top of the floors.

This is due to an implementation of certain effects that causes symbols and other images to be redrawn and placed on top after effects have been processed. You can see there are aslo some symbol overlaps that change in your map when effects are turned on.

The simple way to fix this is to type the command DELAYDRAWSYM on the command line, the command prompt will switch to a prompt asking if they should be enabled, then just type 0 and hit enter to turn this feature off.

The cause of your problem is that border around the hieroglyphs at the top of the map. It is placed at the map border layer, which means it redefines the position of the map border, and most drawing tools are designed to stop drawing at the border.

YouTube is somewhat peculiar when you post several videos at once. I've seen the same happen with videos from others I follow, my subscriber stream only lists the first video even though the rest are available.

I'll try to avoid that in the future, but I couldn't really start a new series with just that intro video alone.