Exact same bug here myself, word for word!
This wasn’t an issue before (and I’ve had my device since late August). I’ve only noticed these wifi issues since the 3.8.4(?) release which addressed the KRACK bug.
I did create a topic for this issue here which might be of some help for the likes of @miska?
EDIT:
I’ve also tried alternating radios. So I typically use the Generic MAC80211 802.11bgn radio for my 2.4GHz wifi but this has caused issues. Since yesterday, I disabled that radio and used the Qualcomm Atheros QCA9880 802.11bgnac radio in 2.4GHz mode for wifi instead. Still the same issues.
This leads me to believe it isn’t an issue with individual radios.