Try reimporting the shader.
Or open it, change something in the Shader Graph, revert the changes back and save.
Or you can send me your project by email (support@infinity-code.com), I will check it.
Or you can use some built-in shader (for example, Unlit / Texture).
Or you can switch to URP or Built-in RP.

Unfortunately, your post does not contain a screenshot.
I have just tested HDRP map and it works correctly.

For Sprite Renderer, the map uses a built-in shader, so if this appears transparent, look for a problem on your side.

For Tileset, the map uses TilesetPBRShader.
If you want to make it unlit, open the shader in Shader Graph and select Graph Settings / HDRP / Material - Unlit.

I have opened plugin (v 3.7) in a new and an empty project with Unity 2020.1.6 with HDRP, and I have opened Tileset example to Fix the materials, and when I inspect the materials they are assigned like it is explained in the documentation, but somehow I get transparent, blurred plane instead of a map (attached image).

I have tried with Unlit / Texture shader, but it looks to me like the map isn't as bright in the Sprite Renderer example.

My question is it needed to continue working with TilesetPBRShader and try to "fix" it somehow, or Unlit/Texture shader is okay?