@Chris_K
It is one and the same file, which is stored in OnedriveCloud, so that I have it on all the computers. At home an iMac and mobile a laptop with Windows 10
1. I created the file to the iMac with 6 pages
2. on the road, I have opened the file (no problems) on the laptop (Windows 10) and added to another page.
3. at home on the iMac, I wanted to continue working on the file and noticed that the 7 page is missing
I can not explain it to me. Maybe the problem in future versions of affinity Publisher no longer occurs.
If I find time on the weekend, I'll try the opposite way. I create a file under Windows with 6 pages and on the Mac to create another page. I will report back...
Greetings