Typing MOSH_ESCAPE_KEY twice sends the escape key twice

[snarkophilus]

With mosh 1.3.2 on MacSS 12.5 (installed via brew) connecting to mosh 1.3.2 on CentOS 7, if I type the escape character (^6) twice, I get two escape characters at the remote end:

-bash-4.2$ hexdump -C
^^^^00000000  1e 1e                                             |..|
00000002

This is different to the description in the ESCAPE SEQUENCES section of the manpage:

        ... To send the escape character itself, type it twice.