ArgumentException at BanDataError

(11:30:44) | EnhancedBanSystem was compiled successfully in 1915ms

(11:30:44) | Unloaded plugin Enhanced Ban System v5.2.6 by Reneb/Slut

(11:30:45) | ExType: JsonSerializationException

(11:30:45) | Failed to call hook 'OnServerInitialized' on plugin 'EnhancedBanSystem v5.2.6' (ArgumentException: Could not cast or convert from System.String to System.Collections.Generic.List`1[Oxide.Plugins.EnhancedBanSystem+BanData].)

at Newtonsoft.Json.Utilities.ConvertUtils.EnsureTypeAssignable (System.Object value, System.Type initialType, System.Type targetType) [0x00062] in <2ae3f091decd4989b3c4d466e6eb5985>:0

at Newtonsoft.Json.Utilities.ConvertUtils.ConvertOrCast (System.Object initialValue, System.Globalization.CultureInfo culture, System.Type targetType) [0x00031] in <2ae3f091decd4989b3c4d466e6eb5985>:0

at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.EnsureType (Newtonsoft.Json.JsonReader reader, System.Object value, System.Globalization.CultureInfo culture, Newtonsoft.Json.Serialization.JsonContract contract, System.Type targetType) [0x0008d] in <2ae3f091decd4989b3c4d466e6eb5985>:0

(11:30:45) | Loaded plugin Enhanced Ban System v5.2.6 by Reneb/Slut

Anyone have any idea about what this could be ?

I'm using the exact same setup on another 2 servers, no errors what so ever - it started happening after last forced wipe.