Polkadot validator produced blocks but submitted no parachain attestations #9999
Description
Polkadot validator 14m...FQ4 had a serious paravalidation issue during Polkadot sessions 11724-11726, and submitted zero attestations throughout this period. Despite this, it continued syncing and successfully authored the following finalized blocks: 28009655, 28010327, 28011668, 28012116, 28012940, 28013155, 28013422, 28014296, 28014505, and 28014825. The hardware also continued to function correctly.
The validator was running the binary polkadot 1.19.2-2caeef482a4 on Debian 12 (Linux kernel 6.1.0-17-amd64). The service is managed via systemd, and the restart was performed using systemctl stop {service_name}.service followed by systemctl start {service_name}.service.
Early in session 11727 (October 2nd), the validator was restarted, after which it resumed submitting attestations, and the issue was resolved. The logs around the time of the failure were similar to the following:
2025-10-02 02:40:36 Some network error occurred when fetching erasure chunk origin=Public(ba078321d7e80f064433061b55ce6483a9abaf2fc9532d7e582c7c344caed415 (15Cv91kh...)) relay_parent=0x9af050c3aee6825c799e821ecaeda4ec6177f4932405a8d95330ead8ba27b88d group_index=GroupIndex(54) session_index=11726 chunk_index=ValidatorIndex(285) candidate_hash=0x5ea41a199d1780f660d3ff33278e21dd982f508e33e225f193fc8cac8be18fff err=Refused traceID=125799497660553122427664690082321670621
Multiple validators on the same server array, with identical hardware and network configurations, operated normally throughout these sessions. The resolution of the issue solely through a restart suggests that it was not caused by any ongoing hardware or network failures.
I'm including the relevant logs for reference.
Thank you for your attention.