Shortening the file name of a .ics event allows it to successfully import in Thunderbird in Events and Tasks. Has this been addressed as a bug that could be worked on?

I have noticed that when a .ics file is not able to be manually imported into Thunderbird via the Events and Tasks there is a way to get it to import. Simply edit the filename of the .ics file to something very short (like less than 8 characters). I'm not sure why longer and more complex .ics filenames fail but shortening the filename almost always works.