Texts from one source are blank but can be read in Notification Centre

Just signed up for Parcel Motel service for Amazon deliveries. Got sent two verification texts from new service. Showed up as new texts, with usual app badge icon, etc, but when I try to read them they appear blank. However when I look in Notification Centre the message body text is visible. Also they will not lose the blue dot no matter how many times I click on them.