As far as I know deals for things like "Future Considerations" are a thing. We traded Chris Spielman many years ago for "Past Considerations" which was quite literally nothing.
We also don't know exactly what the conditions were, it was speculated that they may have been voided, but they may not have. It can always be something like if he appears on the Bills 53 man roster more than 2 games in 2020 or something.