VFX only working when VFX Graph Editor is opened

Hi,
there is an issue with the current version of VFX Graph. I've got a pretty basic effect that is using Output Particle Distortion Quad and it is working fine but only in Editor with the VFX Graph Editor opened. When I close the editor or go into playmode it suddenly dissapears.

My console logs is as follows:

Code (CSharp):

1. Shader error in 'Hidden/VFX/Heatwave/System 1/Output Particle Distortion Quad': undeclared identifier 'alphaMask' at line 1475 (on d3d11)
2.  
3. Compiling Vertex program
4. Platform defines: UNITY_ENABLE_REFLECTION_BUFFERS UNITY_USE_DITHER_MASK_FOR_ALPHABLENDED_SHADOWS UNITY_PBS_USE_BRDF1 UNITY_SPECCUBE_BOX_PROJECTION UNITY_SPECCUBE_BLENDING UNITY_ENABLE_DETAIL_NORMALMAP SHADER_API_DESKTOP UNITY_LIGHT_PROBE_PROXY_VOLUME UNITY_LIGHTMAP_FULL_HDR

Tested on 2019.3 and HDRP 7.2.0. I belive it started happening after 7.1.7 update.

I am attaching a simple .unitypackage that demonstrates the issue.

 

thanks!