Earlier this week Nintendo rolled out Version 6.0.1 of Splatoon 3. Although it's failed to fix certain problems associated with the latest Big Run event, apparently there's a patch coming in the future that can hopefully address this problem.
Apart from this, Nintendo has shared its usual list of patch notes, so in case you missed it, here they are in full courtesy of the official support page. Once again, this update hasn't fixed the Big Run reward bug: