LOCK / UNLOCK not working wirh urlencoded path

[trupf]

I get the error (translated)

Error while saving the document "xxx y123": The file https://nas.my-server.de/webdav/Dokumente/Urlaub/xxx%20y123.xlsx is locked by you. At the moment no additional write access can be permitted.

Please note the blank in the file name which is urlencoded in the error message. If i use a file name with underscore instead of the blank everything is working. I can also save the file without error, if I remove the locking and unlocking from my nginx server setup. So I guess the error is in the locking / unlocking code resp. the code asking for write permission.