How to reproduce:
1. Open attached project "20192BetaExperiments.zip" and scene "Init"
2. Resize Game window (resizing vertically seems to reproduce the issue faster)
3. Observe yellow circle

Expected result: the full circle is always lit
Actual result: sometimes a gap in the 360 degrees light circle appears

Reproducible with: 2019.2.0f1 (6.7.1, 6.9.0), 2019.3.0a10(7.0.0)
Could not test with: 2019.1.12f1 and older due to Sprite2D package errors AND 2019.3.0a10 LWRP 6.9.0 and lower due to package errors

* Settings falloff Intesity to 0 or Inner and Outer angle to 360 helps in reproducing/seeing the issue
* The 2d experimental light feature is implemented in LWRP 6.7.1 and was not available in 6.5.3 and older package versions