[BUG] Hyperkitty cron jobs never finish

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Tag/version of Container Images
Choose from: 0.4.6 (but also seen on 0.4.4 and 0.4.5)

Hyperkitty cron jobs never finish and when I attach strace I see the following:

...
close(21299706)                         = -1 EBADF (Bad file descriptor)
close(21299707)                         = -1 EBADF (Bad file descriptor)
close(21299708)                         = -1 EBADF (Bad file descriptor)
close(21299709)                         = -1 EBADF (Bad file descriptor)
close(21299710)                         = -1 EBADF (Bad file descriptor)
close(21299711)                         = -1 EBADF (Bad file descriptor)
close(21299712)                         = -1 EBADF (Bad file descriptor)
close(21299713)                         = -1 EBADF (Bad file descriptor)
close(21299714)                         = -1 EBADF (Bad file descriptor)
close(21299715)                         = -1 EBADF (Bad file descriptor)
close(21299716)                         = -1 EBADF (Bad file descriptor)
...

I have no idea how to debug this further, logging files for UWSGI are don't mention any errors. The uwsgi process is taking anywhere from 100-400% cpu depending on how many of the cronjobs have started (minutely...yearly).