I'm still convinced that, at some point, the band took an old demo, an old refrain they worked on during the One More Light era, re-adapting the rhythm, lyrics, and timbre. This would also explain the short time it took to condense a new version of the track (starting from October 2024, when the track still had its original layout).
Here's the observation I did about Let You Fade at the time of its release, and the reference to the live performance the band posted during the recording of OML in 2015/16.
live from FB from OML era: https://www.facebook.com/share/v/16EEqvAWXn/ [REMOVED AFTER LYF RELEASE]