This appears to be related to the same problem. Nothing is changed, except the link title, but two signatures are updated.

The problem is related to {{Literatur}}, it only seems to happen if the template is within this specific (or perhaps any other) template:

• Diff Angela Merkel
• Diff Atacama-Humanoid

It might be that this is related to how {{Literatur}} is defined:

{{Literatur|Titel={title}|Online={url}|Abruf=[|Zugriff=]{accesstimestamp:automatic}|Online={linkstring}}}

The Online parameter is defined twice. For dewiki, the correct use is the second one, not the first. I don't know where to change this, but perhaps reducing this to a single Online parameter fixes the issue.

You would go to the Parameter mapping and it will pull up individual maps. Blank fields use the default map for the wiki. You can also use "#REDIRECT[[enwiki]]" or some other acknowledged wiki-code to use a map from that wiki instead.

I tried to find it, but I'm quite confused by the menu structure. Which of the various template pages allows me to change the mapping I pasted above?

I've disabled handling of Literatur. You can disable templates to be handled by inputting "NULL" as the map.

The Template Literatur, per https://de.wikipedia.org/wiki/Spezial:ApiSandbox#action=templatedata&format=json&includeMissingTitles=1&lang=en&titles=Vorlage%3ALiteratur&redirects=1 has a citoid value for URL defined and it is set to Online. This is not correct as URL is for URLs only, not formatted wikitext. This is why the bot is double defining it. It's seeing it as a necessary value to map and then is also map the secondary user defined value. Conversely, Citoid will only put a URL there and not a bracketed URL. Consequently, Citoid might have an issue parsing Literatur templates with bracketed URLs inside them.

On second thought, this might actually be valid. So I should probably amend the bot to handle this.

This should be fixed in beta12.