Is there a bound nΛ3?

The HypHI Collaboration at GSI argued recently for a nΛ3 (Λnn  ) bound state from the observation of its two-body t+π−t+π− weak-decay mode. We derive constraints from several hypernuclear systems, in particular from the A=4A=4 hypernuclei with full consideration of ΛN↔ΣNΛN↔ΣN coupling, to rule out a bound nΛ3.