Fix the file truncating bug

This bug is already mentioned in a CMU issue. It's fixed in Tango-m2 with commit 4010bf84 (on the dev branch). Bonus points if you cherry pick that commit and keep my id on it (this should happen by default with a cherry pick as I understand it).

If you don't cherry pick my commit, the log should clearly indicate this is a bugfix and there is an active PR for it upstream.