I'd consider that as a bug, these elements should be unified because they all do the same thing, with only one distinction — they're placed in different locations. Without paddings or with different backgrounds these elements look weird and clumsy. There are no restrictions that could make this impossible to implement.
On the first screenshot we can use negative margins or flexbox. On the third we just need to add padding and that's all. We also have popup in resource manager that should be fixed.
When it comes to background images — I'd say we better replace them with linear gradients, that way we can get scalable images with no need to disable background images at all. Right now there is a huge inconsistency there: the first one doesn't have an image as it overlaps, second one has it because we have padding there to help us fit this gradient here, and the last one also has a gradient that is now clipped. Second screenshot is the base for all popups and they all should have the same padding in my opinion. I had to fix this in one of my styles because it looks too weird for me.