So I’ve had a few inquiries recently as to why “can’t I upload multiple photos to a post any more?” Don‘t worry you are not going mad- it can still be done despite this recent bug in the recent Insta update.
Go ahead and create a post by selecting the plus sign on your profile ( it has moved to the top right now) and select POST.
You won’t see the multiple option. Choose the first photo as normal then hold it down momentarily. This will allow you to select multiple photos. Voila a work around! I’m sure Instagram will do an update soon but hope this helps in the meantime.