Premiere Pro: “Change Clip Speed (Fit to Fill)” greyed out — and I’ve checked everything

Hey all — running into a weird Premiere Pro issue and hoping someone’s seen this before.

In the Fit Clip window, the option “Change Clip Speed (Fit to Fill)” is greyed out. I've done this a 100 times so it seems to be a new issue. What’s driving me nuts is that I’ve already checked all the usual causes:

• It’s a video clip, not a still

• There is a real gap in the timeline

• The clip duration does not match the gap

• The clip has no speed/duration changes or time remapping

• The clip is not nested

• I’m using Fit to Fill, not overwrite/insert

• The clip is long enough to reasonably fill the gap

Despite all that, the option stays disabled.

Things I’ve tried:

• Removing attributes (nothing to remove)

• New sequence

• New project
• Different clips at same frame rate

• Copying clip into a fresh project

• Restarting Premiere

System details (in case it helps):

• Premiere Pro version: 25.6.4

• Mac Studio M1 OS: macOS Sequoia 15.3.1