Nothing unusual here, BIP141 is the second part of the Segwit2x plan. After locking BIP91, we are in a grace period of 330 blocks where every miner should adopt BIP141 as well, or their mined blocks could be rejected
Consider BIP91 as a mere signal of commitment and BIP141 as the proper activation of Segwit. BIP91 is harmless by itself, is just a voting among miners to know their intentions. If only a few mining pools activate BIP141 directly, by August 1st, once UASF triggers, there would be a chain split. BIP91 is simply a "ok, do we all (80%+) agree on activating BIP141 now and a 2Mb block increase in 3 months?"
That is confusing since bip91 require 80% and bip141 require 95% to activate. As I undetstood bip91 was a way to activate segwit at 80%, not 95%. What you're saying is they still need 95% consensus on bip141 in order to get Segwit the non-uasf way? Is that the bip91 effect of blocking non-segwit blocks that starts soon, to simply force the percentage over 95 threshold and thus activate bip141?