--- Comment #14 from Stéphane Lesimple <[hidden email]> ---
Some new data points:
The oldest version I could try, 8.0-RELEASE, behaves the same with C2 as in any
more recent version (up to HEAD). This problem was hidden before due to the
cx_lowest default always being C1 up to 11.0R.
I also noticed that when C2 is set as cx_lowest, C1 is not used at all. Another
interesting behavior is that the cx_usage_counters increases 10 times faster
with C2 than with C1.
It might also be interesting to note that C3 is ignored even if advertised as
supported (which is probably irrelevant to this bug).