Strange particle rendering behaviour since upgrading to Unity 2019.1.8 from 2018.3

Since we updated the project from 2018.3 to 2019.1.8 our smoke particle has stopped rendering. We can fix it by re-assigning the Sprites/Default (or Diffuse) shader to the material, but as soon as we re-open the project the particle has vanished. We can see that it plays when previewing it, which also includes in game, but as you can see from the attached screenshot it is not rendering. Has anyone else encountered this or similar? A fix would be appreciated as we are now thinking of falling back to 2018.3.14 as particles seem very broken right now.

Swapping to another material and back:



After restarting Unity:

 

Just rolled back to 2018.4.3 and the issue still remains. Back to 2018.3 then I guess.

 

Hi there, thanks for getting back to me on here. I'm not sure if these issues are related (I mean it could be a possibility?) but it states that the problem is reproducible in 2018.3.14f1, but that's the version we were using prior to the update with no problems.

EDIT: Just to clarify, the key issue is we can fix the problem by swapping out the materials but once we restart Unity the problem appears - it seems like something is lost during that process.

 

I will post a bug report, but the steps are;
-- Create empty Game Object
-- Attach a Particle System
-- Create a material, assign a shader like Sprites/Diffuse or Sprites/Default
-- Assign material to particle system, note Particle should be working as normal
-- Save scene and quit Unity
-- Start Unity and open scene with particle system

Expected result: Particle should render in the scene view (and in-game) after selecting it

Actual result: Particle "plays," as illustrated by the orange outline in my screenshots, but the sprites themselves are invisible.

Is this enough for a bug report, do you think? I won't be able to upload the project, but I could potentially upload a stripped down version with just the particle system in question.