So there is this thing with tiled backgrounds that include transparency. Since they are tiling, the trilinear (and bilinear) filtering methods will cause part of the non-transparent part to bleed onto the transparent part (and vice versa). They were mentioned every now and then and I think that was also the reason why the 1px transparent border was added when cropping in Construct to mitigate that issue.
I sometimes see sprites still do this regardless, but it´s rare. I assume it´s because of the spritesheeting going on, that if the sprite happens to be in an "unlucky" spot and at certain zoom levels it can end up bleeding. Here's an example of a sprite having bleeding. In this case it is scaled down quite a bit (used as a more distant object). Looking at the spritesheet it´s quite obvious what causes the bleed. Note that both sprites have the 1px extra border.
One thing I noticed it that the lines will not appear if the game is at the intended zoom level. But once you zoom, scale the game (by scaling the window) or scaling the layout/layer with events, the lines will start creeping in. After some testing I noticed that zooming in is less of a problem, and an additional 1px added will prevent the lines from appearing. When zooming out, even with 2 or 3 pixels extra it will eventually bleed, though you really have to zoom out quite a bit for that.
I just think this shouldn´t be a thing, and I know that setting sampling to nearest completely solves this, but I like my smooth edges, I don´t want jaggies. There must be a way to get rid of this... please :V
Found this info on disabling mipmapping or using texture arrays, sounds kinda promising if possible. Especially the mipmapping since different zoom levels seem to be the main cause of that issue.