Like all tools, the Detail tool remembers all of its last settings, or the setting that are picked up with the eyedropper from a placed detail.
It sounds like someone left the file you're working on with the Detail Tool set to link to a particular detail, rather than to create a new one. Check the settings vs those in the screenshot attached here.
One of the forum moderators
AC 28 USA and earlier • macOS Sonoma 14.7.1, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB