The first time the cache is refreshed after updating to 0.11 gives lots of errors like

(appstreamcli:6240): GLib-CRITICAL **: g_variant_get_type: assertion 'value != NULL' failed

(appstreamcli:6240): GLib-CRITICAL **: g_variant_type_is_subtype_of: assertion 'g_variant_type_check (type)' failed

(appstreamcli:6240): GLib-CRITICAL **: g_variant_get_int32: assertion 'g_variant_is_of_type (value, G_VARIANT_TYPE_INT32)' failed

It only happens the first time, any subsequent cache refresh finishes without errors. The refresh seems to finish correctly despite the errors, but it certainly looks scary (and I'm already getting reports about it downstream)