For 1.
Sounds like a bug. When a texture is created from an image the code specifies whether the texture repeats or is clamped. So looks like construct recognizes that it’s the same texture and reuses it but doesn’t change the repeat mode of the texture.
For 2.
Tiledbg has a texture per instance. By default it loads the default one when creating, but when you load a texture it replaces it on that instance alone.
Sprites have their textures in an animation structure that’s shared between instances. So if you replace a texture it affects all instances.
I thought they added a way to add frames at runtime too for sprites. But overall the textures are loaded in specific ways per type.