So I made an encounter with two monsters. One was a custom monster and the other is a standard monster. On the page for the encounter, without starting the encounter or anything, I can see both the custom stat block as well as the normal monster. I can select the normal monster first and then the custom monster, but if I select the custom monster and then the normal monster I get a white space in between the header and footer on the normal pages. There is a "Report feedback" button in the top left corner of the white space, but that does not seem to be linked to anything. It says it's the same page as the encounter so it's not redirected or anything.
So I made an encounter with two monsters. One was a custom monster and the other is a standard monster. On the page for the encounter, without starting the encounter or anything, I can see both the custom stat block as well as the normal monster. I can select the normal monster first and then the custom monster, but if I select the custom monster and then the normal monster I get a white space in between the header and footer on the normal pages. There is a "Report feedback" button in the top left corner of the white space, but that does not seem to be linked to anything. It says it's the same page as the encounter so it's not redirected or anything.
This sounds as though the issue might be related to the custom monster. Can you post a link to both the homebrew monster and to your encounter?
Encounter: https://www.dndbeyond.com/encounters/3437dc29-b053-432a-8eae-49c2ac53d00b
Monster: https://www.dndbeyond.com/monsters/1854069-zedrem