Why it is a question
A35 §10: “Can we characterize pragmatic fidelity as a form of approximate bisimulation between communicative systems, and then determine which aspects of their noncommutative update structure must be preserved for that bisimulation to hold?” A38 gave it a section (labelled transition systems, Milner, van Glabbeek, Desharnais et al.) and in §11.4 already doubted it: “Consider whether bisimulation is too strong and whether weaker trace equivalence is more appropriate.”
Why it was set aside
Under U16, A39 put “observational equivalence at the center of the formal theory, and treat[ed] intertwining, bisimulation, and quantum contextuality as progressively stronger structures whose usefulness must be justified”. A40 ordered the candidates as static response, finite-sequence observational, trace, simulation and bisimulation, “noting that exact logical relationships depend on the chosen system model”, and closed: “The earlier version risked jumping from pragmatic framing to noncommuting operators to bisimulation before showing why that additional mathematical structure was necessary.”
An answer would name a judgement that finite-sequence observational equivalence (TERM-033) gets wrong and bisimulation gets right. The one-way case survives as CLAIM-034.
The record has since read the first formal object for it, and it does not reopen the question. THEORY-247 (LIT-962) identifies the discounted bisimulation metric with a bicausal transport distance, and THEORY-280 (LIT-948, LIT-962) estimates it from samples. Both are for chains without actions only. Neither supplies a judgement on which TERM-033 and bisimulation disagree.