If I reply, but do not choose to "Include the text of the original message", then I get a blank message (as expected), but there is no signature in it.
This is a change from 4.61, which did show the signature even when not including the original text. (I have "Add this variant upon message creation" checked.)
It appears that the signature is added as the message is sent, and shows up in the version delivered to addressees, but is not included in the version that shows up in the "Copy self" folder (again, a change from 4.61). (I have 4.61 running on a second machine at home and have done side by side tests.)
It's a small thing, but I liked the way the signature appeared in 4.61. Is this a bug, a misconfiguration on my part, or ...?
(Longtime user and fan of the program.)