I'm riding since about a decade singlespeed and later fixed gear, 3 different bicycles, had to tension my chain numerous times over that period, and never noticed any tension variation noticable to me and no I'm not blind heh.
It's only since my latest fixed gear, but as explained, it's certainly not the chainring mount that is the (by far) main reason, it's the 48/16.
Maybe a remaining question: my plan is thus to change to 47, so that there is a rotation of chain links engaging teeth at peak force moments - I wonder is there any way to quantify the wear spreading. For ex my 48/16 could be quantified as a zero spreading / worst case scenario.
Because, it's an annoyant problem, you feel it when pedaling and I'm forced to tension abit too much on the least loose point, without my chain hangs way too lose on the most loose point, risking falling off.
Adding another question about chainrings offcenter, don't they "recenter" too?
Because, if forces cause them to move abit on their mount, then forces can bring them back, at least in the case of fixed gear, when one can put force in the opposite direction.
This is also something that you may feel underway.