In response to 0.0.0.0 day, Firefox Nightly version 131 had introduced a new security measure: blocking access to 0.0.0.0/::/::ffff:0.0.0.0 addresses. This change is currently live for Nightly users and will be gradually rolled out to all release users in the near future. Before we implement this ch...
Do you have standard Firefox with default options that does this? This has not been my experience.
You could try out with a new profile if it works out the same.
I just tried to use the Developer version. With no addons.