It's pretty infuriating but if you have filters on you filter out your homebrews. There is no function as far as I know in which you can filter by what you own AND have your homebrews up on the list. One of my complaints as well, in addition to the fact that there is no simple "Filter by owned" option.

...I feel like this would have been fixed had the acquisition hadn't happened.  D&DB was faster on updates and more responsive pre-acquisition. 

I'm having the issue. I tried clearing all of my filters in the encounter builder, but none of my homebrew monsters will show up both newly created today and from over a month ago.

I've waited a few days and still cannot add homebrew monsters in the encounter creator.

Anyone know how to file a ticket? I can't find a way to do it.

Like some others have mentioned, it seems filters are the problem. If you have the "remember my filters" box ticked, click the "clear all filters" button on the bottom left side of the encounter builder editor and all new homebrew monsters should appear then. A little bit annoying that you will have to reconfigure your filters again, but, at the very least, we have a temporary work around.

I've tried unselecting the "remember my filters" and clicking the "clear all filters", but my homebrew monsters still don't show up.

I've given up on the encounter builder at this point. Probably will switch my party off of DND Beyond when my subscription ends.

Holy crap, this is happening to me! I have created many homebrew monsters before and never had this issue. Just now I created one and it won't show up!!! My game is tomorrow, this is very upsetting. 

I don't have any filters and it's still not showing up. :-( 

Just to chime in with my experience since it's been a while since the last post - Unchecking 'remember my filters' and then clicking 'Clear All Filters' actually did work for me.  Not ideal by any means, but it did the trick.