Earthquake clusters example broken since v3.11.0

[dtreiter]

The earthquake cluster example has an issue when hovering over a cluster.

Expected behavior

Should display the features which are part of the cluster.

Actual behavior

Rapidly blinks between showing the individual features and showing the cluster when the mouse is moving through a cluster's circle.

Verified in Chrome and Firefox.

To reproduce

Go the earthquake cluster example and mouse over a cluster:
Earthquake Example

Note that this seems to be working prior to v3.11.0. For example, v3.10.1 is fine.
v3.10.1 Example

[ahocevar]

Thanks for the great bug report. This looks like a regression, and i already have an idea what might be causing it. I'll investigate more after getting some sleep.

[ahocevar]

I am working on this right now.