Here are the steps I've taken to reproduce the issue:
Make a new scene, delete default camera
Create tk2dCamera, tk2dTileMap, tk2dSprite
Switch tk2dCamera's Camera -> Rendering path from player settings to vertex lit
Ensure that sprite collections for the tilemap and sprite have Normal Mode set to Normals only
Adjust ambient scene lighting to a low setting
Change shader material on tilemap chunks and sprite to tk2d/LitBlendVertexColor, confirm there is difference in light shading
Add Point Light to scene, move it around, observe lighting on tilemap and sprite
I recorded myself doing these steps so you can see my results:
https://www.youtube.com/watch?v=Sy4tSO2bAzYAfter recording this I made a brand new spritecollection with a spare texture file I had and it actually worked! So clearly there's something wrong with the sprirecollection I'm trying to use but I guess I don't know enough about tk2d to identify it straight away. Maybe there's something you can see in the sprite editor (I show it near the end of the video) that I'm missing?