I looked at the article you referred to, which suggested that the error may be caused by having a non-public individual as default for the tree. This is not the case for either of the trees on my Kiwitrees web site.
In fact there is something strange about the error messages, which I didn’t mention. The IP address of the web site which was accessing the file was something like 18.104.22.168. I did an nslookup for this IP address, and it gave the result:
name = petalbot-114-119-148-10.petalsearch.com
And it turns out that petalsearch.com is a Web search site. On the “Privacy” statement of the site it states that:
“Petal Search is a product (web service) provided by Aspiegel SE, a Huawei subsidiary incorporated in Ireland”
Anyway, I guess there’s not much I can do about these annoying intrusions.