It sounds as if you are saying the problem is that you do not change the font but for some reason it gets set to 1638 point font. Is that the problem?
It is interesting that you set only one byte -- Chr(10) -- for the CrLf -- on a Windows OS. Normally Windows OSes expect 2 byte line ending Chr(10) & Chr(13) CrLf.
Why aren't you using
Constants.vbCrLf
?
I mention this because it could be that there is an odd offset byte thing since Outlook probably expects the document body to be UTF-8 and that is defined as: "UTF-8 is a variable width character encoding capable of encoding all 1,112,064[1] valid code points in Unicode
using one to four 8-bit bytes."*
When you see these odd things in text it is often this type of thing : where a system attempts to make sense of a stream of bytes but cannot.
As a test, maybe remove the Chr(10) entirely and see what you get. If you can attempt to replace them with
Constants.vbCrLf
.
*from
UTF-8 - Wikipedia[
^]