Instrumentation amplifier and op amp V+ and V- shorted internally
The bulk of ICs made today have internal ESD protection diodes on any I/O pin, configured like this.







simulate this circuit &ndash; Schematic created using CircuitLab

During normal operation, the only time these diodes become forward biased is when the pin is exposed to a voltage outside the power rails. Poking around an unpowered chip with a DMM, it's entirely possible to measure a short between the power rails. Reverse the leads and it will appear open. Your test is invalid for determining if the ICs are good.