diff --git a/internal/caching/cache_lazy_load_members.go b/internal/caching/cache_lazy_load_members.go
index 198983767..a4fda99ef 100644
--- a/internal/caching/cache_lazy_load_members.go
+++ b/internal/caching/cache_lazy_load_members.go
@@ -3,8 +3,6 @@ package caching
 import (
 	"fmt"
 	"time"
-
-	"github.com/matrix-org/gomatrixserverlib"
 )
 
 const (
@@ -34,16 +32,13 @@ func NewLazyLoadCache() (*LazyLoadCache, error) {
 	return &LazyLoadCache{cache}, err
 }
 
-func (c *LazyLoadCache) StoreLazyLoadedMembers(reqUser, deviceID, roomID, userID string, event *gomatrixserverlib.HeaderedEvent) {
+func (c *LazyLoadCache) StoreLazyLoadedUser(reqUser, deviceID, roomID, userID string) {
 	cacheKey := fmt.Sprintf("%s/%s/%s/%s", reqUser, deviceID, roomID, userID)
-	c.Set(cacheKey, event)
+	c.Set(cacheKey, true)
 }
 
-func (c *LazyLoadCache) GetLazyLoadedMembers(reqUser, deviceID, roomID, userID string) (*gomatrixserverlib.HeaderedEvent, bool) {
+func (c *LazyLoadCache) IsLazyLoadedUserCached(reqUser, deviceID, roomID, userID string) bool {
 	cacheKey := fmt.Sprintf("%s/%s/%s/%s", reqUser, deviceID, roomID, userID)
-	val, ok := c.Get(cacheKey)
-	if !ok {
-		return nil, ok
-	}
-	return val.(*gomatrixserverlib.HeaderedEvent), ok
+	_, ok := c.Get(cacheKey)
+	return ok
 }
diff --git a/syncapi/streams/stream_pdu.go b/syncapi/streams/stream_pdu.go
index 02e19bd2c..b345e4f2c 100644
--- a/syncapi/streams/stream_pdu.go
+++ b/syncapi/streams/stream_pdu.go
@@ -459,7 +459,7 @@ func (p *PDUStreamProvider) lazyLoadMembers(
 			continue
 		}
 		// membership is not yet cached, add it to the list
-		if _, ok := cache.GetLazyLoadedMembers(device.UserID, device.ID, roomID, event.Sender()); !ok {
+		if !cache.IsLazyLoadedUserCached(device.UserID, device.ID, roomID, event.Sender()) {
 			timelineUsers[event.Sender()] = struct{}{}
 		}
 	}
@@ -471,7 +471,7 @@ func (p *PDUStreamProvider) lazyLoadMembers(
 			if _, ok := timelineUsers[event.Sender()]; ok {
 				newStateEvents = append(newStateEvents, event)
 				if !stateFilter.IncludeRedundantMembers {
-					cache.StoreLazyLoadedMembers(device.UserID, device.ID, roomID, event.Sender(), event)
+					cache.StoreLazyLoadedUser(device.UserID, device.ID, roomID, event.Sender())
 				}
 				delete(timelineUsers, event.Sender())
 			}
@@ -495,7 +495,7 @@ func (p *PDUStreamProvider) lazyLoadMembers(
 	}
 	// cache the membership events
 	for _, membership := range memberships {
-		cache.StoreLazyLoadedMembers(device.UserID, device.ID, roomID, membership.Sender(), membership)
+		cache.StoreLazyLoadedUser(device.UserID, device.ID, roomID, membership.Sender())
 	}
 	stateEvents = append(newStateEvents, memberships...)
 	return stateEvents, nil