diff --git a/lib/charms/prometheus_k8s/v0/prometheus_scrape.py b/lib/charms/prometheus_k8s/v0/prometheus_scrape.py
index e4297aa1..665af886 100644
--- a/lib/charms/prometheus_k8s/v0/prometheus_scrape.py
+++ b/lib/charms/prometheus_k8s/v0/prometheus_scrape.py
@@ -362,7 +362,7 @@ def _on_scrape_targets_changed(self, event):
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 42
+LIBPATCH = 44
 
 PYDEPS = ["cosl"]
 
@@ -386,6 +386,7 @@ def _on_scrape_targets_changed(self, event):
     "basic_auth",
     "tls_config",
     "authorization",
+    "params",
 }
 DEFAULT_JOB = {
     "metrics_path": "/metrics",
@@ -764,7 +765,7 @@ def _validate_relation_by_interface_and_direction(
     actual_relation_interface = relation.interface_name
     if actual_relation_interface != expected_relation_interface:
         raise RelationInterfaceMismatchError(
-            relation_name, expected_relation_interface, actual_relation_interface
+            relation_name, expected_relation_interface, actual_relation_interface or "None"
         )
 
     if expected_relation_role == RelationRole.provides:
@@ -857,7 +858,7 @@ class MonitoringEvents(ObjectEvents):
 class MetricsEndpointConsumer(Object):
     """A Prometheus based Monitoring service."""
 
-    on = MonitoringEvents()
+    on = MonitoringEvents()  # pyright: ignore
 
     def __init__(self, charm: CharmBase, relation_name: str = DEFAULT_RELATION_NAME):
         """A Prometheus based Monitoring service.
@@ -1014,7 +1015,6 @@ def alerts(self) -> dict:
                 try:
                     scrape_metadata = json.loads(relation.data[relation.app]["scrape_metadata"])
                     identifier = JujuTopology.from_dict(scrape_metadata).identifier
-                    alerts[identifier] = self._tool.apply_label_matchers(alert_rules)  # type: ignore
 
                 except KeyError as e:
                     logger.debug(
@@ -1029,6 +1029,10 @@ def alerts(self) -> dict:
                 )
                 continue
 
+            # We need to append the relation info to the identifier. This is to allow for cases for there are two
+            # relations which eventually scrape the same application. Issue #551.
+            identifier = f"{identifier}_{relation.name}_{relation.id}"
+
             alerts[identifier] = alert_rules
 
             _, errmsg = self._tool.validate_alert_rules(alert_rules)
@@ -1294,7 +1298,7 @@ def _resolve_dir_against_charm_path(charm: CharmBase, *path_elements: str) -> st
 class MetricsEndpointProvider(Object):
     """A metrics endpoint for Prometheus."""
 
-    on = MetricsEndpointProviderEvents()
+    on = MetricsEndpointProviderEvents()  # pyright: ignore
 
     def __init__(
         self,
@@ -1836,14 +1840,16 @@ def _set_prometheus_data(self, event):
             return
 
         jobs = [] + _type_convert_stored(
-            self._stored.jobs
+            self._stored.jobs  # pyright: ignore
         )  # list of scrape jobs, one per relation
         for relation in self.model.relations[self._target_relation]:
             targets = self._get_targets(relation)
             if targets and relation.app:
                 jobs.append(self._static_scrape_job(targets, relation.app.name))
 
-        groups = [] + _type_convert_stored(self._stored.alert_rules)  # list of alert rule groups
+        groups = [] + _type_convert_stored(
+            self._stored.alert_rules  # pyright: ignore
+        )  # list of alert rule groups
         for relation in self.model.relations[self._alert_rules_relation]:
             unit_rules = self._get_alert_rules(relation)
             if unit_rules and relation.app:
@@ -1895,7 +1901,7 @@ def set_target_job_data(self, targets: dict, app_name: str, **kwargs) -> None:
             jobs.append(updated_job)
             relation.data[self._charm.app]["scrape_jobs"] = json.dumps(jobs)
 
-            if not _type_convert_stored(self._stored.jobs) == jobs:
+            if not _type_convert_stored(self._stored.jobs) == jobs:  # pyright: ignore
                 self._stored.jobs = jobs
 
     def _on_prometheus_targets_departed(self, event):
@@ -1947,7 +1953,7 @@ def remove_prometheus_jobs(self, job_name: str, unit_name: Optional[str] = ""):
 
             relation.data[self._charm.app]["scrape_jobs"] = json.dumps(jobs)
 
-            if not _type_convert_stored(self._stored.jobs) == jobs:
+            if not _type_convert_stored(self._stored.jobs) == jobs:  # pyright: ignore
                 self._stored.jobs = jobs
 
     def _job_name(self, appname) -> str:
@@ -2126,7 +2132,7 @@ def set_alert_rule_data(self, name: str, unit_rules: dict, label_rules: bool = T
                 groups.append(updated_group)
             relation.data[self._charm.app]["alert_rules"] = json.dumps({"groups": groups})
 
-            if not _type_convert_stored(self._stored.alert_rules) == groups:
+            if not _type_convert_stored(self._stored.alert_rules) == groups:  # pyright: ignore
                 self._stored.alert_rules = groups
 
     def _on_alert_rules_departed(self, event):
@@ -2176,7 +2182,7 @@ def remove_alert_rules(self, group_name: str, unit_name: str) -> None:
                 json.dumps({"groups": groups}) if groups else "{}"
             )
 
-            if not _type_convert_stored(self._stored.alert_rules) == groups:
+            if not _type_convert_stored(self._stored.alert_rules) == groups:  # pyright: ignore
                 self._stored.alert_rules = groups
 
     def _get_alert_rules(self, relation) -> dict: