lava_flow (and water_flow) does not have a blockstate or model json file

both of the liquid's flowing textures do not have a related blockstate of model json file resulting in their rendering to be hardcoded and cannot be changed with a resource pack without the use of external clients such as optifine

 

Note this can be easily confused with the generic texture file being missing but please do not make that connection as it is not relevant

 

I found this glitch as I was trying the change the rendering code of flowing lava