DescentBB

To put it simply, I've converted the levels in The Countdown to vertigo and added the corresponding bots.
Unfortunately, when I go into the mines, the vertigo bots are replaced with D1 bots.
I've heard of this situation before but couldn't find any solution, hence this post.

Check your .mn2 file.
It should read 'zname = (name of your mission)' instead of 'name = (name of your mission)'.

The 'z' makes it a Vertigo-enabled mission, so D2 can read it correctly.

Thats unexpectedly really simple. I thought it would be more difficult to solve.
It just goes to show how important it is to get everything right. Even down to a single letter.
Thanks for the help.

Just make sure to include d2x.ham (renamed after your hog file) in your mission. A side effect of Rebirth removing persistent mods from mission to mission (so you don't i.e. fight enemy within mechs while playing some random mission) was that Vertigo mechs also aren't persistent, leading to missing robot errors.