Office/Onedrive path length limit problems
Path length limit in OneDrive (business) in filesystem does not match the limits in Office in collaboration mode
When working on OneDrive for business in Office (Word in the example), you sometimes cannot save a file right next to an existing file, using the same number of characters (when path length is long). The reason seems to be that is that path length check does not take URL expansions into account (spaces in path becomes %20 and then count as three chars).
I ended up disabling collaboration features, forcing Word to use Windows file API instead of the sharepoint web API, but that shouldn't be necessary.
I know this is actually an error report, but in lack of an error reporting system, it is posted here as proposed by MS in the above linked thread.