Thanks for your bug report. In this case, /play is passing the name of the window and the text to the /echo alias you have specified. However, as /echo has never supported window names with spaces, it treats "status window test" as plain text.
Other commands that support window names with spaces require them to be enclosed in quotes, eg. "Status Window". So, in order to resolve the issue you are seeing, /play would need to be changed to enclose window names in quotes, and /echo would need to be changed to parse window names in quotes. Unfortunately, both of these changes have the potential to break existing scripts.
