Creating smart playlist makes media library inaccessible

[plex_junix_systems]

Hi,

Every time I create a smart playlist (in this case, resolution = 4k), the library in which I create is becomes in accessible with the error: " There was an unexpected error
Please visit our forums if you continue to experience problems".

Logs on the server do not reveal much:

Mar 23, 2021 10:44:14.898 [0x7fa579b31700] DEBUG - Auth: authenticated user 1 as plex@email.address
Mar 23, 2021 10:44:14.898 [0x7fa555ffb700] DEBUG - Request: [10.11.12.92:64650 (Allowed Network (WAN))] GET /library/sections/6/all?type=1&decade=1980&sort=year%3Adesc&includeCollections=1&includeExternalMedia=1&includeAdvanced=1&includeMeta=1 (5 live) TLS Page 0-49 GZIP Signed-in Token (plex@email.address)
Mar 23, 2021 10:44:14.900 [0x7fa555ffb700] ERROR - Unknown metadata type: folder
Mar 23, 2021 10:44:14.900 [0x7fa555ffb700] DEBUG - Setting container serialization range to [0, 49] (total=-1)
Mar 23, 2021 10:44:14.906 [0x7fa555ffb700] DEBUG - Setting container serialization range to [0, 49] (total=1)
Mar 23, 2021 10:44:14.909 [0x7fa579b31700] DEBUG - Completed: [10.11.12.92:64650] 200 GET /library/sections/6/all?type=1&decade=1980&sort=year%3Adesc&includeCollections=1&includeExternalMedia=1&includeAdvanced=1&includeMeta=1 (5 live) TLS GZIP Page 0-49 10ms 2489 bytes (pipelined: 1)
Mar 23, 2021 10:44:14.925 [0x7fa579330700] DEBUG - Auth: authenticated user 1 as plex@email.address
Mar 23, 2021 10:44:14.925 [0x7fa555ffb700] DEBUG - Request: [10.11.12.92:64650 (Allowed Network (WAN))] GET /hubs/search?includeCollections=1&includeExternalMedia=1&contextual=1&contentDirectoryID=6%2C1%2C2%2C4%2C3&sectionId=6&query=marriage (5 live) TLS GZIP Signed-in Token (plex@email.address)
Mar 23, 2021 10:44:14.962 [0x7fa579330700] DEBUG - Completed: [10.11.12.92:64650] 200 GET /hubs/search?includeCollections=1&includeExternalMedia=1&contextual=1&contentDirectoryID=6%2C1%2C2%2C4%2C3&sectionId=6&query=marriage (5 live) TLS GZIP 36ms 1673 bytes (pipelined: 2)