SG GST charged to GST-registered Business and inconsistency across accounts

Is anyone else encountering the same problem with Singapore GST-registered businesses? I find it peculiar that out of my 10+ business plans, I’m being levied a 9% GST for half of them, while the remaining half isn’t subject to it.

My ticket has been open for over 2 weeks and I’ve not heard from support despite my follow-up email.
Ticket id: 3236476

Hey there, sorry about that. I’ll let our billing specialist take a look at it.