I've got an IBM 3161 ASCII terminal hooked to my linux box. Whenever I open a manpage, I get the letter 'm' before every newline. Additionally, I get the message 'HOST PROG WRONG' on my terminal's message line, due to invalid escape codes.

Piping 'man' through 'less' extenally (I am aware it already acts as the pager by default) fixes this. I logged some output via 'socat' and saw that each line, instead of ending with the CRLF that my terminal wants, was ending with '\033[m\r\n' (ESC, [, m, CR, LF). The problem appears to be related to setting attributes under an assumption of what the terminal needs, without checking in termcap.

Here's a photo of what a typical manpage looks like:
http://i.imgur.com/zz5Xmys.jpg