[Help] VSRO - NPC Creation - Not able to buy items past tab 4

Hey guys!

I've recently started creating a new NPC Vendor and I've come across a problem.

I've created 6 Groups and 10 Tabs for the NPC which all worked fine,
but once I've started filling those Tabs with items I noticed something odd.

I can only buy items off the store if they are located in TAB1-TAB4,
I can't buy any items of TAB5-TAB10 even tho they are all identical.

Kinda looks like this:

NPC:
GROUP1 = TAB1(buyable)
GROUP2 = TAB2(buyable)
GROUP3 = TAB3(buyable), TAB4(buyable), TAB5(not buyable)
GROUP4 = TAB6(not buyable), TAB7(not buyable), TAB8(not buyable)
GROUP5 = TAB9(not buyable)
GROUP6 = TAB10(not buyable)

I thought 4 tabs might be the cap for a NPC to hold, but some NPCs in Alexandria even have 12 working TABs.

Any help would be appreciated!