Check podbot.cfg file, there should be something like this:
# These lines below are adding automatically the bots to the server when
# the new game is created on the listenserver or the dedicated server
# is starting.
# As many such lines like "pb add" is here as many bots will be added
# to the server (unless You will not exceed pb_maxbots setting).
pb add 100
pb add 100
pb add 100
pb add 100
pb add 100
pb add 100
Leave the ones you want, in this example 6 bots with 100 skill wil be automatically added.