i was watching [Sexy] Vietnam War 118.157.93.209:15567 and one of the players became a bot then about 5 mins later he wasnt, is this normal or is there something "untoward" going on?

There are a variety of reasons why some players can be detected as bots. They include:

Server reports them as bots
Server reports them with negative play times.
The player’s name is modeled after a typical bot name, eg Bot1, Bot2, etc.

I would recommend downloading HLSW (hlsw.org), then view the server looking at the player list to determine if it has unusual ping or reporting that could be the cause.