diff --git a/build/docker/Dockerfile.monolith b/build/docker/Dockerfile.monolith
index 0d2a141ad..891a3a9e0 100644
--- a/build/docker/Dockerfile.monolith
+++ b/build/docker/Dockerfile.monolith
@@ -1,4 +1,4 @@
-FROM docker.io/golang:1.17-alpine AS base
+FROM docker.io/golang:1.18-alpine AS base
 
 RUN apk --update --no-cache add bash build-base
 
@@ -23,4 +23,4 @@ COPY --from=base /build/bin/* /usr/bin/
 VOLUME /etc/dendrite
 WORKDIR /etc/dendrite
 
-ENTRYPOINT ["/usr/bin/dendrite-monolith-server"]
\ No newline at end of file
+ENTRYPOINT ["/usr/bin/dendrite-monolith-server"]
diff --git a/build/docker/Dockerfile.polylith b/build/docker/Dockerfile.polylith
index c266fd480..ffdc35586 100644
--- a/build/docker/Dockerfile.polylith
+++ b/build/docker/Dockerfile.polylith
@@ -1,4 +1,4 @@
-FROM docker.io/golang:1.17-alpine AS base
+FROM docker.io/golang:1.18-alpine AS base
 
 RUN apk --update --no-cache add bash build-base
 
@@ -23,4 +23,4 @@ COPY --from=base /build/bin/* /usr/bin/
 VOLUME /etc/dendrite
 WORKDIR /etc/dendrite
 
-ENTRYPOINT ["/usr/bin/dendrite-polylith-multi"]
\ No newline at end of file
+ENTRYPOINT ["/usr/bin/dendrite-polylith-multi"]
diff --git a/syncapi/storage/postgres/memberships_table.go b/syncapi/storage/postgres/memberships_table.go
index 8c049977f..00223c57a 100644
--- a/syncapi/storage/postgres/memberships_table.go
+++ b/syncapi/storage/postgres/memberships_table.go
@@ -64,7 +64,7 @@ const selectMembershipCountSQL = "" +
 	") t WHERE t.membership = $3"
 
 const selectHeroesSQL = "" +
-	"SELECT user_id FROM syncapi_memberships WHERE room_id = $1 AND user_id != $2 AND membership = ANY($3) LIMIT 5"
+	"SELECT DISTINCT user_id FROM syncapi_memberships WHERE room_id = $1 AND user_id != $2 AND membership = ANY($3) LIMIT 5"
 
 type membershipsStatements struct {
 	upsertMembershipStmt      *sql.Stmt