Warning when creating material.

I've been struggling to make material for my partickle effects.
I want a simple cloud with lightning, using " texture and sheet animation"
I am creating "png file" in GIMP with black background and white layer of couds and lightning.
Material in unity im making is:
Legacy shaders ->partickles->additive
In partickles i mdragging said material onto material.
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At this point things pretty much work as i want them to work, its just matter of settings BUT
wheni m clicking on maerial and resizing any unity window im getting warnings :
Internal: JobTempAlloc has allocations that are more than 4 frames old - this is not allowed and likely a leak
To Debug, enable the define: TLA_DEBUG_STACK_LEAK in ThreadsafeLinearAllocator.cpp. This will output the callstacks of the leaked allocations

Is that something i shoudl be concerned about?
And how to fix those?
since it sais its " legacy shader" how to make non-legacy shader for my purpose?
Ps: i am a beginner, i appreaciate your effort in helping me, but please keep in mind i may struggle in understanding too advanced answers.

 

That error is a Unity bug; there are a few of these in recent versions, but it's generally not something you need to worry about.

And to pick a non-legacy shader, simply don't use the "Legacy Shaders" portion of the shader pop-up menu. Use the regular Particles submenu else instead.

 

Im asking about that non-legacy shaders, becouse for some reaosn i don't have additive there.Just standard unit and surface.

 

Which release of Unity are you on?

 

I have same problem.

I checked it in Unity 2018.3.2f1 and 2018.3.7f1.
Two version has same warning issue