Clicking on 'Create Issue' from classic boards results in 500 error

{"message":"Can not deserialize instance of java.util.ArrayList out of VALUE_STRING token\n at [Source: org.apache.catalina.connector.CoyoteInputStream@1c294b2; line: 1, column: 22] (through reference chain: com.atlassian.jira.quickedit.rest.api.UserPreferences[\"fields\"])","status-code":500,"stack-trace":"org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of VALUE_STRING token\n at [Source: org.apache.catalina.connector.CoyoteInputStream@1c294b2; line: 1, column: 22] (through reference chain: com.atlassian.jira.quickedit.rest.api.UserPreferences[\"fields\"])\n\tat org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163)\n\tat org.codehaus.jackson.map.deser.StdDeserializationContext.mappingException(StdDeserializationContext.java:219)\n\tat org.codehaus.jackson.map.deser.StdDeserializationContext.mappingException(StdDeserializationContext.java:212)\n\tat org.codehaus.jackson.map.deser.std.StringCollectionDeserializer.handleNonArray(StringCollectionDeserializer.java:210)\n\tat org.codehaus.jackson.map.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:156)\n\tat org.codehaus.jackson.map.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:146)\n\tat org.codehaus.jackson.map.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:18)\n\tat org.codehaus.jackson.map.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:299)\n\tat org.codehaus.jackson.map.deser.SettableBeanProperty$FieldProperty.deserializeAndSet(SettableBeanProperty.java:579)\n\tat org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:697)\n\tat org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:580)\n\tat org.codehaus.jackson.map.ObjectMapper._readValue(ObjectMapper.java:2695)\n\tat org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1308)\n\tat org.codehaus.jackson.jaxrs.JacksonJsonProvider.readFrom(JacksonJsonProvider.java:419)\n\tat com.sun.jersey.spi.container.ContainerRequest.getEntity(ContainerRequest.java:474)\n\tat com.sun.jersey.server.impl.model.method.dispatch.EntityParamDispatchProvider$EntityInjectable.getValue(EntityParamDispatchProvider.java:123)\n\tat com.sun.jersey.server.impl.inject.InjectableValuesProvider.getInjectableValues(InjectableValuesProvider.java:46)\n\tat com.atlassian.plugins.rest.common.interceptor.impl.DispatchProviderHelper$EntityParamInInvoker.getParams(DispatchProviderHelper.java:159)\n\tat com.atlassian.plugins.rest.common.interceptor.impl.DispatchProviderHelper$ResponseOutInvoker._dispatch(DispatchProviderHelper.java:228)\n\tat com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)\n\tat com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)\n\tat com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)\n\tat com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)\n\tat com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)\n\tat com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)\n\tat com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1469)\n\tat com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1400)\n\tat com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)\n\tat com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)\n\tat com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)\n\tat com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)\n\tat com.atlassian.plugins.rest.module.RestDelegatingServletFilter$JerseyOsgiServletContainer.doFilter(RestDelegatingServletFilter.java:178)\n\tat com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:795)\n\tat com.atlassian.plugins.rest.module.RestDelegatingServletFilter.doFilter(RestDelegatingServletFilter.java:73)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat