Failed to fetch themes error

I can reproduce this on self-hosted and non-atomic sites (atomic sites don't seem to be affected). When I go to Themes in the main menu, the themes are loaded but I see this toast message:

Stacktrace:

Volley error on https://public-api.wordpress.com/rest/v1.1/sites/107699613/themes/mine/?locale=en_US
com.android.volley.ParseError: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 1313 path $.taxonomies
at org.wordpress.android.fluxc.network.rest.GsonRequest.parseNetworkResponse(GsonRequest.java:100)
at com.android.volley.NetworkDispatcher.processRequest(NetworkDispatcher.java:144)
at com.android.volley.NetworkDispatcher.processRequest(NetworkDispatcher.java:111)
at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:90)
Caused by: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 1313 path $.taxonomies
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:397)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.readIntoField(ReflectiveTypeAdapterFactory.java:212)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$FieldReflectionAdapter.readField(ReflectiveTypeAdapterFactory.java:433)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:393)
at com.google.gson.Gson.fromJson(Gson.java:1227)
at com.google.gson.Gson.fromJson(Gson.java:1137)
at com.google.gson.Gson.fromJson(Gson.java:1047)
at com.google.gson.Gson.fromJson(Gson.java:982)
at org.wordpress.android.fluxc.network.rest.GsonRequest.parseNetworkResponse(GsonRequest.java:95)
at com.android.volley.NetworkDispatcher.processRequest(NetworkDispatcher.java:144)
at com.android.volley.NetworkDispatcher.processRequest(NetworkDispatcher.java:111)
at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:90)
Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 1313 path $.taxonomies
at com.google.gson.stream.JsonReader.beginObject(JsonReader.java:393)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:386)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.readIntoField(ReflectiveTypeAdapterFactory.java:212)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$FieldReflectionAdapter.readField(ReflectiveTypeAdapterFactory.java:433)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:393)
at com.google.gson.Gson.fromJson(Gson.java:1227)
at com.google.gson.Gson.fromJson(Gson.java:1137)
at com.google.gson.Gson.fromJson(Gson.java:1047)
at com.google.gson.Gson.fromJson(Gson.java:982)
at org.wordpress.android.fluxc.network.rest.GsonRequest.parseNetworkResponse(GsonRequest.java:95)
at com.android.volley.NetworkDispatcher.processRequest(NetworkDispatcher.java:144)
at com.android.volley.NetworkDispatcher.processRequest(NetworkDispatcher.java:111)
at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:90)

Start with the themes request at https://public-api.wordpress.com/rest/v1.1/sites/107699613/themes/mine/?locale=en_US and the GsonRequest.parseNetworkResponse method in GsonRequest.java. Reproduce the failure on a self-hosted or non-atomic site, then trace the themes response model around the taxonomies field. Done means Themes loads without the failed-fetch toast for the affected response.