When two UCANs get bundled into an amplification UCAN, its time bounds must be within the intersection of the bundled UCAN time bounds, as per the spec.

The time bounds MUST also be equal to or contained inside the time bounds of the proof's time bounds.

This accidentally attenuates time bounds, could we avoid it?

E.g., by allowing time bounds to be derived from the proof chain, preserving original time bounds of each bundled capability.
The concept @Gozala introduced, being discussed here.

E.g., to have time bounds at the capability level, perhaps in Caveats.

E.g., to represent amplification as a collection of UCANs
Pro: preserves granularity of capabilities, allowing to manage them separately, e.g., revoking only some.
Con: these UCANs would need to be individually authorized. Something that attenuation as a bundled UCAN spares us from.
Con: and individually revoked later on, if one wishes.