Oh crap. The foundation has moved and this is disconnected again.

Foundation inspection showing differences. That corner of the main house is heaving up rather than sinking down, and the addition is sinking slightly.

Photo by pest control showing foundation movement

Photo by pest control showing foundation movement

Photo by pest control showing foundation movement

January 2022 - sketch of foundation remediation plans

May 2022 - state of laundry room foundation before work started

December 2023 Foundation inspection showing differences. That corner of the main house is heaving up rather than sinking down, and the addition is sinking slightly.