You have an ADCON0 assignment just prior to each ADCIN statement.
Code:
ADCON0=%11001101 'Sets up the AtoD Module to read Channel 1
ADCIN 1, A2D_V2 'Read channel 1 to A2D_V2 Value
That will change the channel and start the conversion immediately without allowing for acquisition time.
This leaves the voltage from the previous channel in the sample&hold capacitor.

The ADCIN statement handles ADCON0 for you, so Removing the ADCON0 lines should help.

You can also reduce the ADC_SAMPLEUS 400 to around 50 or less.
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