Speed / Duration Greyed out can't slow down clips

I've just had this issue. That box has never, ever, ever been greyed out before. But now it is. Why?

Did i "get around" it? Yes, I nested the clip on its own in a nest of itself, on its own, and reversed the nest.

But why should I have to do that? Why should that be the answer?

I see the other suggestesions for fixing this problem... "make a whole new file, copy this one clip into there, reverse it, copy it back", "Clear the Cache", and certainly "Reinstall Everything" should never, ever, ever be the solution for this kind of problem.

The only solution to this problem is Adobe users should demand that Adobe fix their broken software, and then Adobe make better software. To see community experts not also suggesting this is just so sad. Community shills, morelike.

You might try creating a NEW project and importing the problem clip into it, it might be better to make a copy of the clip (IE: a name you have not used before) and bring that in, and check if it works.

If that doesn't work, before you uninstall and reinstall:

Delete the Media Cache and Media Cache files:
https://community.adobe.com/t5/premiere-pro/faq-how-to-clear-your-media-cache-in-30-seconds-in-premiere-pro-2020/m-p/11017257/thread-id/260446?page=1

If that doesn't work,try resetting the preferences:
https://community.adobe.com/t5/premiere-pro/faq-how-to-reset-trash-preferences-in-premiere-pro/td-p/8236158?page=1

If that doesn't work, try resetting the Workspaces:
Reset a workspace
Reset the current workspace to return to its original, saved layout of panels.
1. Do one of the following:
• Click the Workspace menu icon and select Reset to Saved Layout.
• Choose Window > Workspace > Reset to Saved Layout.
from here:
https://helpx.adobe.com/premiere-pro/using/workspaces.html

If that doesn't work, try Preferences > Audio Hardware and set Input to None.

If that doesn’t work, try updating or rolling back your graphics driver directly from the video card manufacturer’s site.

If that doesn't work, try creating a new project and import the old one into it.

Try changing the speed without the other effect(s) applied and then nest.  Apply the other effects to the nest.

Does anyone know a fix for this?

Since you are going to slow down the clip i assume that you are not going to save/use the audio since it will be slowed down as well. If that´s the case, click anywhere in the timeline to de-select any selected clips. Then, press and hold the Alt-key on the keyboard while selecting the video portion of the clip. This will only select the video clip and leave the audio out. Then press Ctrl+R and try to change the speed. Did it work?

Has it worked before to change the Speed by percentage when using BRAW footage? I have no footage to try on, hence the question. 🙂

Nest the clip and apply the speed/duration to the nest.

Sorry I realized I left out some vital information and I don't know how to edit my post 

PP Version - 14.7 ( Latest ) 
Clips i'm trying to slow down as normal are 60FPS on a 24FPS timeline.