Originally Posted by scottfro
My place is kept at around 65C.
Theres your problem, most yeast die around 55C, Im amazed you can live in that sort of environment.
Assuming you meant 65F, is it constant or does it dip lower at night? A rapid temperature drop could shock the yeast into hibernation (Ive had this happen with 3787 in the 60s). Lack of aeration is a good guess as well, try giving your next batch a good shake after you release the vacuum and see if your problems go away.
For this batch stick it somewhere warm and see if the yeast get moving again.