The movement stat is not being reset, although it does look like it. I saw the same thing, and thought the same as you guys did. Then I did some looking around, and figured it out.
If you mouseover the "Movement" stat, the tooltip breaks down where all your moves come from. It will look something like "1.2 from base stat, +1 from Adventurer" etc. So that alone would give 3 moves - 2 from the 1.2 stat, and 1 from Adventurer.
When you level up & add 0.2 to the move score, it will show 3.2 Moves. But if you mouseover the stats again, it will now show "1.4 from base stat, +1 from Adventurer", which will still give you 3 moves - 2 from the 1.4 stat, and the extra. And the next time you level, it will show 3.0 Moves again.
However, the experience books (and "book containing ancient knowledge") do not work for me.