Yeah, that happened to me when white resigned.
Horde bug || Time forfeiting leads to a draw
Another bug: my opponent was able to force a draw by spam clicking the offer draw button (I kept playing and did not accept). The chatbox said he resigned, but the popup said draw
Same bug happened to me in this game:
https://www.chess.com/variants/horde/game/10429270/95/3
As black it is a clearly won position and my opponent surrendered, but it showed a draw on my screen...
Recently I played horde variant with black pieces and after my opponent realised that he has no chances left he just waited for a minute until his time ran out and the game ended with a draw :/