diff --git a/include/libtorrent/disk_io_job.hpp b/include/libtorrent/disk_io_job.hpp
index 0fb4fb786..c3c9dc477 100644
--- a/include/libtorrent/disk_io_job.hpp
+++ b/include/libtorrent/disk_io_job.hpp
@@ -196,7 +196,7 @@ namespace libtorrent {
 		status_t ret = status_t::no_error;
 
 		// flags controlling this job
-		disk_job_flags_t flags{};
+		disk_job_flags_t flags = disk_job_flags_t{};
 
 		move_flags_t move_flags = move_flags_t::always_replace_files;
 
diff --git a/src/disk_io_thread.cpp b/src/disk_io_thread.cpp
index 3fb9a949b..3be0f0b34 100644
--- a/src/disk_io_thread.cpp
+++ b/src/disk_io_thread.cpp
@@ -2882,6 +2882,7 @@ constexpr disk_job_flags_t disk_interface::cache_hit;
 
 		disk_io_job* fj = allocate_job(job_action_t::flush_storage);
 		fj->storage = j->storage;
+		TORRENT_ASSERT(fj->flags == disk_job_flags_t{});
 
 		int ret = j->storage->raise_fence(j, fj, m_stats_counters);
 		if (ret == aux::disk_job_fence::fence_post_fence)
diff --git a/src/disk_job_fence.cpp b/src/disk_job_fence.cpp
index 0ed093f4d..779ccd7a8 100644
--- a/src/disk_job_fence.cpp
+++ b/src/disk_job_fence.cpp
@@ -181,6 +181,7 @@ namespace libtorrent { namespace aux {
 	int disk_job_fence::raise_fence(disk_io_job* j, disk_io_job* fj
 		, counters& cnt)
 	{
+		TORRENT_ASSERT(!(j->flags & disk_io_job::in_progress));
 		TORRENT_ASSERT(!(j->flags & disk_io_job::fence));
 		j->flags |= disk_io_job::fence;
 
@@ -214,6 +215,7 @@ namespace libtorrent { namespace aux {
 #endif
 			m_blocked_jobs.push_back(fj);
 			cnt.inc_stats_counter(counters::blocked_disk_jobs);
+			TORRENT_ASSERT(!(j->flags & disk_io_job::in_progress));
 		}
 		else
 		{