Servitors are flying, but fall through the floor when they follow me.

(346hp 456m 539mv 14947tnl) u
The first floor of the keep



(346hp 456m 536mv 14947tnl) e

An earth elemental has arrived.
A radiant archon has arrived.
You hear a loud snapping as the rotting wooden floor gives way!
A radiant archon falls through the rotting wooden floor!
An earth elemental falls through the rotting wooden floor!

>Servitors are flying, but fall through the floor when they
>follow me.

If they're flying they won't fall through the floor. Since neither comes into the game flying, you would have had to make them fly through a staff/wand/scroll/etc. I'd guess you are mistaken.