diff --git a/include/haproxy/receiver-t.h b/include/haproxy/receiver-t.h
index e4e9b2922..d1897de51 100644
--- a/include/haproxy/receiver-t.h
+++ b/include/haproxy/receiver-t.h
@@ -64,7 +64,6 @@ struct rx_settings {
 struct shard_info {
 	uint nbgroups;                         /* number of groups in this shard (=#rx); Zero = unused. */
 	uint nbthreads;                        /* number of threads in this shard (>=nbgroups) */
-	ulong tgroup_mask;                     /* bitmask of thread groups having a member here */
 	struct receiver *ref;                  /* first one, reference for FDs to duplicate */
 	struct receiver *members[MAX_TGROUPS]; /* all members of the shard (one per thread group) */
 };
diff --git a/src/listener.c b/src/listener.c
index 0ad6d7c84..69344d356 100644
--- a/src/listener.c
+++ b/src/listener.c
@@ -882,9 +882,7 @@ struct shard_info *shard_info_attach(struct receiver *rx, struct shard_info *si)
 	}
 
 	rx->shard_info = si;
-	BUG_ON (si->tgroup_mask & 1UL << (rx->bind_tgroup - 1));
-	si->tgroup_mask |= 1UL << (rx->bind_tgroup - 1);
-	si->nbgroups     = my_popcountl(si->tgroup_mask);
+	si->nbgroups++;
 	si->nbthreads   += my_popcountl(rx->bind_thread);
 	si->members[si->nbgroups - 1] = rx;
 	return si;
@@ -913,8 +911,7 @@ void shard_info_detach(struct receiver *rx)
 	BUG_ON(gr == MAX_TGROUPS);
 
 	si->nbthreads   -= my_popcountl(rx->bind_thread);
-	si->tgroup_mask &= ~(1UL << (rx->bind_tgroup - 1));
-	si->nbgroups     = my_popcountl(si->tgroup_mask);
+	si->nbgroups--;
 
 	/* replace the member by the last one. If we removed the reference, we
 	 * have to switch to another one. It's always the first entry so we can