I'm using the following connexions for pic16F684. It is connected to a 8*2 LCD display.
Power supply is 9V duracell with 5V L7805 voltage regulator.

VDD: +5V
VSS: 0V
There is a ceramic disk 0.1 UF capacitor between VSS and VDD pins.

I enabled PORTA on-change interrupts because I need to monitor for a 5V pulse on RA5 which is default low (I disabled WPU and set the port as output and set PORTA.5=0)

RA0: nothing connected, output, WPU disabled
RA1: nothing connected, output, WPU disabled
RA2: nothing connected, output, WPU disabled
RA3: nothing connected, with an external 10k weakPU between the pin and +5V, INT enabled
RA4: nothing connected, internal WPU enabled, INT enabled
RA5: nothing connected, WPU DISABLED, INT enabled

RC0: lcd data bit 4
RC1: lcd data bit 5
RC2: lcd data bit 6
RC3: lcd data bit 7
RC4: with an external 10k weakPU between the pin and +5V, LCD R/S bit
RC5: LCD Enable bit

When I touch any pin, an int is triggered on portA.5 (RA5).

WHY???