3-wire strain gauge - HX711 Issue
In your diagram, the fixed 1KΩ resistors both tie to +5V at one set of ends, and their other ends tie to A+ and A-.  The strain gauges are from A+ to ground and A- to ground.  

In a typical scale, where several strain gauges are similarly loaded, that topology will produce about zero volts between A+ and A-.  By contrast, the following  topology (from: blog.l3l4.com) produces higher voltages for higher loading.  (Diagram uses S+, S- rather than A+, A-)

(I realize your question shows some voltage changes when sensors are separately loaded, so this answer might not be relevant to your current problem.)