Pixel problems in fullscreen mode

I am using SDL_RenderSetLogicalSize to scale my 1024x768 game window to fullscreen.
It works but when blitting tiles, some of them are 1 pixel off. The tile source is like 1 pixel to the left.
What am i doing wrong?

fullscreen:

windowed:

Code:
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, 0);
SDL_RenderSetLogicalSize(this->SDLRenderer, 1024, 768);

Well, seems to be a SDL bug:
https://forums.libsdl.org/viewtopic.php?t=10945

I am trying to figure out how to do the fullscreen scaling / letterboxing myself without the corrupt SDL_RenderSetLogicalSize.
Plan: Render the graphics to a surface / texture (?). Then render this surface/texture to the screen scaling it to the fullscreen resolution.
Can anyone point out how this is done?

It’s not an SDL bug. Read the last post in that thread:

“So after all that and a bug report, it comes down to the GPU handling of texels. The way around it is to just add an empty pixel border around every single image and sprite frame you do. It’s not fun, but it’s worth it… grumble… grumble…”