In K8 we have this new feature that we have 2 gridsizes instead of 1. Special for all graphic elements we have a much finer gridscale. It is a neat feature, but it does come with a drawback.
The schematic sheet tiles fall under the fine grid size unfortunately. It makes it kinda hard to align things 'n such.
It does not break anything and you can just live with and make schematics, it is just sorta annoying. It interferes with my works of art
EDIT:
No, it is actually really annoying, see screenshot. I can’t ‘just’ connect busses to the labels. I have to do all kind of workarounds
Just like the regular grid in previous KiCad versions should always be set to a “workable” settings (1.27mm (50mils) works good), you still have to keep the “connected items” and “wires” on a grid that is compatible with easily making connections. (I’m not sure why those two have separate settings).
In the preferences, you see checkboxes for the grid overrides, and you can turn them off. You can also turn them off With the Grid + lock button in the toolbar on the left side.
First, it helps to set a hotkey to “Edit Grids” in the “Common” section (saves “mousing” around the screen).
Place as many grids as you want in the Grids column. The whole list appears for each “Grid Overrides” item when the triangle is clicked. Choose whatever you wish. See red arrow and rectangles for Grids and Opened Graphics Override.
Change the Override for Text if you wish.
You can also leave the Text grid alone but turn off the override, and change one of the Fast Grids, (green arrow and box). This means you can still use 10 mil for your project but use Alt+2 to swap to 25 mil for your Sheet Title.
Lots of combinations are available. Choose to suit yourself
(Beer?) is much better than (I really dislike milk in coffee)
I do all my schematics on a 100-mil grid. Never had a connection issue unless I inadvertently turned off the grid or hit the N key (now disabled). Any denser grid and the schematic does not print well, so I don’t understand the need to go finer. The exception is when moving refs and values around and snuggling them into position, but then the control key lets you do that easily. All wires (and library component pins) are on the 100-mil grid.
The problem with a 100mil grid is that common resistors and capacitors have the attachment points for the wires 300mil apart. That puts them off grid if those parts are moved by their center and for that reason I use a 50mil grid. R_Small and C_Small have their pin spacing at 200mil which makes it easier to use a 100mil grid, but with R_Small you can’t put the value inside the resistor, so it takes up more space overall.
But everything put together. Because there are more grid options, it is a little bit more work to set them up, but once done, connections are just as easy to make as in previous KiCad versions. Disabling (or moving) the Switch to next Grid function, seems sensible, apparently relatively many people mess up their grid by accidentally pressing the N hotkey, and overall, changing grids quickly (or at all) is not very important for the schematic editor anyway. the Switch to next Grid function is in the “common” section though, so if you disable it, it gets disabled in all editors.
Personally, I made “Switch to next Grid” “Alt + N” so I don’t have to keep one eye on the grid notification at the bottom of the screen.
N became “Edit Grids” because I prefer to select grids rather than scroll through the list, especially in Symbol Editor where I will often use all seven (mainly for graphics) showing in the above screen grab.
N has become “Edit Grids” ever since Kicad 6, or 7 (I can’t remember).
It would be nice if if hotkey settings were carried over between Kicad versions.
I never used different grid sizes in schematic. Until I discovered that hitting N ruined my schematics. I turned the ‘N’ hotkey off as fast as I could.
I understand the given solutions, so thank you for those
I do like that I can move other graphical stuff where I want. I think it is a good feature.
I do find it really strange that a schematic sheet is treated differently than symbols and wires. I mean what possible goods can come from schematic sheets having an other, much finer gridsize by default? It will only result in hierarchial labels ending somewhere where you can’t get wires or busses to connect. So IMO sheets should be on the same grid as the symbols or wires at all times.
(I really dislike milk in coffee) 
