Probably, those reports have restarted Bitcoin Core without removing --reindex arg, doing so will restart the reindex process from start.
If you closed Core properly (./bitcoin-cli stop) and considering that there's no other issue, then, your node should resume the progress when you shutdown your node.
But it should be SOP to check the logs before using commands like --reindex since it may not be the best solution that you need.
And now, there should be an indication why it's stalled or at least tell that there's no issue but slow sync progress.