Thanks for reporting. There is a proposed fix[1], which is claimed to resolve the issue[2].
Could you try to verify whether this change resolves the issue for you. There is an amd64 package available at [3], from a merge-request against the packaging[4]. [1]: https://github.com/dovecot/core/pull/133 [2]: https://dovecot.org/pipermail/dovecot/2020-August/119668.html [3]: https://salsa.debian.org/cgzones/dovecot/-/jobs/943580 [4]: https://salsa.debian.org/debian/dovecot/-/merge_requests/16
