Clusters do not spiderfy on click under Leaflet 1.9.0

[lucaswerkmeister]

• I'm reporting a bug, not asking for help
• I'm sure this is a Leaflet.MarkerCluster code issue, not an issue with my own code nor with the framework I'm using (Cordova, Ionic, Angular, React…)
• I've searched through the issues to make sure it's not yet reported

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How to reproduce

• Leaflet version I'm using: 1.9.0
• Leaflet.MarkerCluster version I'm using: 1.5.3
• Browser (with version) I'm using: Firefox Developer Edition 104
• OS/Platform (with version) I'm using: Ubuntu 22.04 Jammy Jellyfish
• create a marker cluster group with several closely adjacent markers and add it to a map
• click the group

What behaviour I'm expecting and which behaviour I'm seeing

I expect the group to “spiderfy”, showing the individual markers. But nothing actually happens.

Minimal example reproducing the issue

https://plnkr.co/edit/UJsTp5X6jabP8v0L

Working 1.8.0 version for comparison: https://plnkr.co/edit/ZxyGxSnT6Ke1EvdG

• this example is as simple as possible
• this example does not rely on any third party code

[indigoxela]

See also: Leaflet/Leaflet#8450

[Falke-Design]

Will be fixed in Leaflet core

[lucaswerkmeister]

Fixed in 1.9.1: https://plnkr.co/edit/j1UtvZzuYo8PYSfW

Thanks @Falke-Design!