weird bug makes me lose 2 inventory slots

[gtsecc]

Normally I have 8 inventory slots, right?
Her is how I seem to lose 2:

I have 2 black market slots, Spy Drone and Neural Interface both maxed 3 canisters each.

Then I have Arm Strength and Run Speed maxed with non black market mods, 3 canisters each.
No worries yet.

Now, if I add a new black market mod - let’s say the Bot Domination over the Arm Strength – BOOM, I lose 2 inventory slots and all those items fall to the ground.

Bug?
Normal?

[Catman]

The strength biomod gives you additional carrying capacity, so when you change that out for one of the other options, you lose those extra slots. It's a perfectly normal part of the game.