Reproduction steps:
1. Open the attached project ("case_1243927-BundleWarningWebGL.zip")
2. Switch build target to WebGL
3. Open the repro scene ("SampleScene")
4. Open Addressables Groups window
5. Set "Play Mode Script" to "Use Existing Build"
6. Build bundles
7. Enter Play Mode while inspecting Console window

Expected result: Warning about bundles built for WebGL being incompatible with the Editor is not cleared
Actual result: Warning can briefly be seen and then it is cleared after entering Play Mode

Reproducible with: 2018.4.23f1, 2019.4.0f1, 2020.1.0b12, 2020.2.0a14
Reproducible with package versions: 1.1.5, 1.9.2
incompatible bundles warning is being immediately cleared out when entering Play Mode

Note: The warning is being cleared out immediately because it is thrown while still in Edit mode, and the Console has the "Clear on Play" setting turned on by default.