We also ran into this error this week, querying Weaviate was not possible anymore, the error from the Weaviate log was as follows:
{"action":"hybrid","build_git_commit":"unknown","build_go_version":"go1.21.13","build_image_tag":"unknown","build_wv_version":"1.25.11","error":"explorer: get class: vector search: object vector search at index pagenode_v4: shard pagenode_v4_Lly8mf7irQs5: build inverted filter allow list: fetch doc ids for prop/value pair: nested query: nested child 0: bucket for prop req_permissions_nullState not found - is it indexed?","level":"error","msg":"denseSearch failed","time":"2024-09-04T08:33:27Z"}
Interestingly, also backups were not possible anymore, with the following error messages (error actually occurred while backing up another collection than the one that shows the error while querying):
{"action":"create_backup","backup_id":"2024-09-04-page_v4","build_git_commit":"unknown","build_go_version":"go1.21.13","build_image_tag":"unknown","build_wv_version":"1.25.11","level":"error","msg":"upload backup class Page_v4 descriptor: list shard WiRWeiVpM70X files: node name: failed to execute query: could not get shard owner: shard not found: \u003cnil\u003e","time":"2024-09-04T08:50:29Z"}
{"action":"create","backup_id":"2024-09-04-page_v4","build_git_commit":"unknown","build_go_version":"go1.21.13","build_image_tag":"unknown","build_wv_version":"1.25.11","level":"error","msg":"coordinator: backup class Page_v4 descriptor: list shard WiRWeiVpM70X files: node name: failed to execute query: could not get shard owner: shard not found","time":"2024-09-04T08:50:31Z"}
A restart of Weaviate fixed these issues, just wanted to let you guys know as these problems seem to be in some way interconnected as they occurred at the same time for us.