Change the display quality using :CC2RESMODE:. Set it to Fixed - High or very high. After doing that, you can try setting it back to automatic and clearing the bitmap cache, but if the issue remains, just leave it at fixed.

CC3+ uses 4 different resolutions for performance reasons, and what you see here is one of the lower texture resolutions being displayed instead of the higher one that probably should have been displayed in that situation.

Note that "Sample size" is just the size of the sample window, it doesn't affect the drawing.

File -> Save as, then pick an image type such as .jpg. You'll probably want to hit the options button in the dialog AFTER picking the file type to set up the resolution you need.

This is a lesser-seen case of the 'Transparency Acne' effect. CC3+ calculates edges by looking for differences in colors.

What happens here is that the lines doesn't go on top of the text, but because the text appears on top of the halftone lines, CC3+ sees differences where the fill has white pixels, and unchanges where they are black. This causes the glow on the text to behave as if the text was full of little holes, and fills those holes with the white glow.

The best way of handling that is to change the colors on your underground railroads from black to a dark grey, just pick the darkest one. Since it isn't black, CC3+ will see that as a difference, and you are fine.

Did you try Shessar's workaround above?

It shouldn't default to that folder, but every now and then something happens which causes the save dialog to open in that folder. This is a problem you can encounter in most windows programs, because you really want to let the dialog remember where the users where saving the files instead of forcing them to a specific directory each time, and this remembering is taken care of by the underlying Windows system, not the program itself.

The important thing in any program is to save your work where you want it, not where the program defaults to, as having control over your own data files makes it much easier to both find them outside the program and handling things like backups.