Reproduction steps:
1. Open the user's attached "VFXEmissionBugExample.zip" project
2. Open SampleScene in Assets/Scenes folder
3. Open "Emission Example.vfx" in the Assets folder
4. Observe Sample Gradient Node Time value (= 1)
5. Observe Cube in Game View
6. Connect Random Number Node output "r" (min <=> max = 1) to the Sample Gradient Node input "Time"
7. Observe Cube in the Game View

Expected result: Cube Particles glow in orange color normally
Actual result: Cube Particles glow in orange color excessively

Reproducible with: 12.0.0 (2021.2.0b9, 2022.1.0a6)
Couldn't test with: 7.7.1 (2019.4.30f1) - the scene becomes white (possibly downgrading issue), 10.6.0 (2020.3.17f1), 11.0.0 (2021.1.19f1) - when random number applied, the Emission example Cube becomes black with a few colored dots (possibly downgrading issue)

Note:
The issue reproduces only when the Random Number Node Seed is set to Per Particle.