diff --git a/timecache/first_seen_cache.go b/timecache/first_seen_cache.go
index f8626ae..351631c 100644
--- a/timecache/first_seen_cache.go
+++ b/timecache/first_seen_cache.go
@@ -29,7 +29,8 @@ func (tc FirstSeenCache) Add(s string) {
 
 	_, ok := tc.m[s]
 	if ok {
-		panic("putting the same entry twice not supported")
+		log.Debug("first-seen: got same entry")
+		return
 	}
 
 	// TODO(#515): Do GC in the background
diff --git a/timecache/time_cache.go b/timecache/time_cache.go
index f10ff21..2a67b4a 100644
--- a/timecache/time_cache.go
+++ b/timecache/time_cache.go
@@ -1,6 +1,12 @@
 package timecache
 
-import "time"
+import (
+	"time"
+
+	logger "github.com/ipfs/go-log/v2"
+)
+
+var log = logger.Logger("pubsub/timecache")
 
 type Strategy uint8