This is happening to me. Has Adobe ever come up with a fix for this???

Exactly the same problem... but more detail in mine:
Had this problem for a while but ignored it!... Once created on my MacPro in InDesign 16.4, I then 'Publish Online...' to allow users to view the publication at our events to view primarilly on Smart Phones. I am the creator of the content, and I use an iPhone 10 on iOS 14.8... and when I test the published document there is a fundamental problem with the zoom function. If you attempt to pinch the screen to zoom in to actually read the text, it starts to zoom and then 'jumps' to closer zoom, and then you cannot scroll down or zoom out!! Once that first zoom has happened, the navigation at the bottom of the screen disappears, and you cannot navigate or zoom out! So the only option you have is to click 'Done' in the top right, which throws you out of the Publish Online web page. I'm publishing information that needs to be zoomed in slightly to read, but when it just jumps into a closer zoom it only shows the top half of the screen, and you cannot scroll down... so frustrating and embarrassing as the creator of this content.

I consider each device and versions involved in this to be pretty industry standard - creating on a Mac, publishing to read and test on a reasonably up-to-date iPhone... but I and our readers are having these navigation issues. I'm paying a monthly fee for the software, but Adobe isn't delivering the fundamental functions needed, unless there is a solution to this problem I am unaware of?
My publication is at: https://indd.adobe.com/view/0cbd5c45-31f1-422c-9795-4cd1e0279ea9

I have the same problem. Viewers on mobile cannot zoom out, they have to quit and reopen. My client is not very happy…

Publish Online 파일을 생성한 후 아이폰에서 열면 safari 나 chrome 에서는 확대를 했다가 다시 축소가 되지 않습니다.
그런데 Explorer app을 다운 받아서 Explorer로 열면 확대 축소가 잘 됩니다.