the question is forced; the answer is open.
every observer’s measurement basis moves under interaction (forced: incoming writes project nonzero onto the observer’s state space) and returns to the birth-shaped attractor (forced: indelibility — ground.md).
continuous retention is bounded: 0 < retention < 1. lower bound from indelibility. upper bound from the impossibility of invariance (perfect invariance would require the observer’s basis to be in the kernel of all incoming writes, not generically achievable).
at stationarity, write directions are effectively random (geometry.md: write blindness). the expected perturbation magnitude per step is determined by the overlap singular values — continuous retention is spectral.
discrete recommitment (re-performing the birth-type commitment operation) provides an alternative return mode, outside the map. recommitment preserves birth shape: the attractor is indelible regardless of what commitments are made.
the adjacency flip (conservation.md) provides the mechanism: interaction-layer adaptations decay when the neighbor set changes.
the specific continuous retention rate at given parameters. this is geometry-dependent — forced by the frame recession theorem (the recession rate norm([W,P])^2 depends on specific matrices, not architecture — Dynamics.lean) — and not derivable from architecture alone.