Disambiguate provider caching

aleksis/apps/tezor/util/invoice.py

@@ -16,8 +16,10 @@ def provider_factory(variant, payment=None):
             "Could not configure payment provider for an invoice group without a client."
         )
 
-    if payment.pk in _provider_cache:
-        return _provider_cache[payment.pk]
+    cache_key = (variant, payment.group.client.pk)
+
+    if cache_key in _provider_cache:
+        return _provider_cache[cache_key]
 
     client = payment.group.client
     provider = None
@@ -49,5 +51,5 @@ def provider_factory(variant, payment=None):
     if provider is None:
         raise KeyError("Provider not found or not configured for client.")
 
-    _provider_cache[payment.pk] = provider
+    _provider_cache[cache_key] = provider
     return provider