[MM3-users] hyperkitty failed to create a thread

Hi all,

What could be a reason of HyperKitty failing to create a thread from chained emails?

For example, see "RECENTLY ACTIVE DISCUSSIONS" on page https://wlug.mailman3.com/hyperkitty/list/wlug@lists.wlug.org/

"Openvpn and Network mapping" discussion displayed as five threads instead of only one...

Any ideas how to improve HyperKitty ability to detect threaded messages?

With my best regards, Danil Smirnov