I have had this problem with Publisher from the first beta until the first production (1.7.1). The text ruler will not always show. I can turn on and off the view text rule to my heart's content, but many times the ruler does not display. It makes it much harder to set tabs without it.
iMac (Retina 5K, 27-inch, 2017)
Processors: 3.8 GHz Intel Core i5
Memory: 24 GB 2400 MHz DDR4
Graphics: Radeon Pro 580 8 GB
No Text Ruler.afpub