The 22ER9051 (bigger/older thumbstick) was based on the Enhanced RC5 standard. It was bundled with the CDI 205, CDI 910 and with early version of the CDI 210 and the CDI 220. The newer/smaller 22ER9055 (The Commander) was based on the RC6 standard. It was bundled with most CD-i players, except for the early ones that included the CD-i Thumbstick. RC6 alows for pressure differences resulting in various cursor movement speeds. So the IR protocol is not the same on all CD-i players. In the comparison table you can find which CD-i player works on which IR standard. That means these controllers will only work on CD-i player that will work with the same IR protocol!
[Thanks, Jaap Jansen]