Are you sure it doesn't stack? Cause other items with Command stack perfectly fine with Competence bonuses on my end, and I'd be surprised if the Command on the augment is any different than the Command on named/random loot.
Regardless, despite this definitely not being the place for this discussion, I'll post my notes regarding THE Command bug:
"Command +X" is bugged. It should add +X Insightful bonus to all CHA skills, but instead of adding the stated X value, it actually adds a higher value (this value, let's call it Y, corresponds to the "Insightful Alluring Skills" bonus of that level, which is the same as the Cannith Crafting Insightful Skill value for said level). This still correctly counts as an Insightful bonus.
This affects named items, randomgen items (namely "Celebrated" ones), and the new Brightbane Emeralds (both varieties). Therefore a decision needs to be made, while keeping in mind that Command affects UMD on top of the other CHA skills:
Do you A) want to bring the actual bonus (Y) down to what's listed (X), in order to keep the balance between Command & Insightful Alluring Skills and avoid UMD inflation? Or B) do you wanna increase the values stated in the effect's description (X) to match what is actually being granted (Y), thus nerfing "Insightful Alluring Skills" (as it doesn't grant Insightful UMD) and also VASTLY increasing a character's available UMD at every level from 1 to 30?
At level 10 for example a Command +4 item currently actually grants +6 Insightful (and thus stacking) UMD. I suppose a third option would be to decouple Command from UMD altogether and keep the values of the current bonuses (Y), and updating the description values (X), but then Command essentially becomes the same as Insightful Alluring Skills.