- Interoperability issues with some older clients and/or drivers resulted in the clients getting into states where they could not pass any traffic (802.11ac Wave 2 MRs)
Wow I thought I was going crazy. Ever since 27.2, all sorts of Apple devices have been doing this while connected to my MR42 but not my MR56.
Overall though the 27.x series seems golden if you have WiFi 6 APs. The MR56 easily got 20-25% faster aggregate throughput with my devices compared to 26.x, which is making them perform more comparably to consumer high end mesh routers like the 8x8 Orbi.
(I know in an enterprise world we might laugh at those devices, but those expensive consumer products seem to perform extremely well)