Cannot "Edit Guide" by percentage - Not Working

Hello ​@William23216329ajmw 

Welcome to the Premiere Forums. We may already be working on this bug, but it would still help us out to know some of your system specs. Please see, How do I write a bug report? for some of the specifics we could use.

For a temporary workaround, I would suggest using the Rectangle tool to create a temporary Graphic Clip. If you set the anchor points to 1, 1 then you can use Transform → Position in the Effect Controls Panel to place a narrow rectangle at the point you want your guide. You can mute or delete these clips to check playback.

Sorry for the inconvenience. We are working on this issue.

Best,

Amy