Have you tried changing your channel name using these steps: Sign in to your channel on YouTube > Click your account icon > settings? Also, in the "Overview" section, click Edit on Google next to your channel name. Update the channel name and click OK. Let us know if this helps.
Please send a feedback report directly from YouTube with these steps: https://goo.gl/WdI0BK . While every individual report may not get a direct response, we do review everything and use the details to investigate and fix issues. Thanks.