The issue is with your shader in blender. The default shader for Sprytile does not import nicely into Godot. I suggest you make an actual Godot Shader. Even when I just used a principle bsdf shader in blender, it still doesn't import everything correctly into Godot. By creating my own custom Godot shader, I avoid that issue. When you import the gltf file into Godot 4.0 you can go to the materials section in import and override the material with your Godot material. If you are using some other engine, the advice remains the same, just create a material within that engine.
Recent community posts
In order to quicken the workflow, it would be excellent to be able to assign a keyboard shortcut to switch into build mode, paint mode, and fill mode. If I press W to select a vertex and make a change to the mesh, I then have to click on the paint tool or build tool to continue working.
A single keypress could bring you from another tool to your last used sprytile tool. Then, if you press it again it could rotate through the sprytile tools. Or you could have a unique key press for each tool.