Since a few days, I have the feeling that there are a lot more blatantly off-topic questions ('lost souls') on Meta Stack Exchange. OK, that could be just a feeling, so I've created a short script (only works for 10k users) to doublecheck. Below is a summary of the number of questions asked per day which are still alive ('OK'), those which have been Deleted (including spam), and Spam posts separately (from this Metasmoke graph):
Date OK Deleted Spam 2018-10-22 9 14 4 2018-10-23 5 20 5 2018-10-24 12 12 4 2018-10-25 13 12 5 2018-10-26 11 13 4 2018-10-27 8 28 11 2018-10-28 7 12 2 2018-10-29 11 31 7 2018-10-30 14 51 7
(the Deleted column will include questions deleted for other reasons than being blatantly off-topic or spam, but those are rare)
This is how that looks in a graph (thanks @Shog9):
So it looks like this wave started on the 29th, which (coincidentally or not) is the day when the 2018 monthly product team updates post was featured (with revision 17). Do the CMs / developers have any way to check if this is really the case, e.g. by checking the Referer header on calls to the Ask Question page? I can't remember other featured posts causing similar waves; the last time was when everybody got an inbox notification about the Terms of Service, which was a much more prominent 'invite' to Meta Stack Exchange.