[arch-proaudio] Archives by thread (messages sorted by thread) - Was: 4.14.18-rt15 Intel Spectre v2 broken microcode detected

FWIW the arch-proaudio archives' thread view is broken, resp. the depth of the thread tree is limited. The thread view is diplayed correctly by claws mail version 3.16.0git24 and evolution 3.26.5, even for mails sent via the mailing list, just the archives' thread view is inconsistent.