Hi Wayne,
I dealt with this infrequently in version 2024 and here are the workarounds that I devised to keep things moving forward.
1) Export plan set pages individually and collate them using Adobe Acrobat or other document managing app.
2) Have all pages up with elevations loaded before export.
3) Change resolution of export to be lower.
4) Use visible line for elevations.
My go-to solution was #2, and if that didn't work #3. I have used all of these at some point with varying levels of success. It would also help at times if I ensured the 3D and all other programs were shut down as I noted that it ate up a lot of my CPU and those spikes/valley are typically where I lost data in the export.
Hope this of some help, welcome back!
Tarah King