Every file that I am opening that has a column sorted by another eg. "Month name" sorted by "Month number" is losing its setting. I noticed after publishing a report that had a chart sorted by month names, that was working fine before.
The fix is simple, just go and sort by the desired column again, but you have to do it for every file and column you have. After that I guess it stays, so probably it was some change on how it works in the newer versions of Power BI Desktop.