diff --git a/src/pread_disk_io.cpp b/src/pread_disk_io.cpp
index 286334bf1c2..8090e02c0ab 100644
--- a/src/pread_disk_io.cpp
+++ b/src/pread_disk_io.cpp
@@ -573,7 +573,9 @@ void pread_disk_io::async_read(storage_index_t storage, peer_request const& r
 		// this is an aligned read request for one block
 		if (m_cache.get({ storage, r.piece }, block_idx, [&](span<char const> buf)
 		{
-			TORRENT_ASSERT(buf.size() <= read_offset + r.length);
+			// if this truly is an aligned read, the block-offset should be 0
+			TORRENT_ASSERT_VAL(read_offset == 0, read_offset);
+			TORRENT_ASSERT_VAL(buf.size() <= read_offset + r.length, r.length);
 			buffer = disk_buffer_holder(m_buffer_pool, m_buffer_pool.allocate_buffer("send buffer"), r.length);
 			if (!buffer)
 			{