This fence tile used to be a corner - I then extended it left words and have just deleted the upwards part of the fence (wood still not collected in picture). Presumably this is the cause of this slight glitch.
Are you trying to build the gate over an existing fence or did you delete that fence segment too before trying to build the gate? I think I normally delete them to reclaim the wood.
I was trying to build over. Of course what I did end up doing was deleting it and building on the empty tile. So it’s not a big issue. Like at all. But it’s a quirky echo of some bugs that were around is 0.9.7p so I reported it completion.
Might also be because it was a corner originally. I’ve knocked a few fence pieces down to place gates and haven’t had that problem, but all my replacements were on straight sections.