Issue with EXP making odd sound

I'm not sure if this is a marlin problem or an issue with my board.

I swapped my last board out because the Z driver quit working.

Over TFT everything seems to work on this one and I can home/move all axis as expected.

The only issue is when I hook up the EXP1 to the EXP3 on the TFT35 E3 touch screen it came with.

It instantly starts making this clicking/beeping that sounds like a metronome.

When I can actually get it to the classic menu it's bounding in and out of the menu like I'm clicking the button.

It does the same thing no matter if I use a new or old cable and does it on the stock display as well.

None of the pins are shorted together on the board connector when I check with a multimeter.

I think I have all the options enabled it said I would need for the screen including #define CR10_STOCKDISPLAY

Anyone seen anything like this before?

Not really the end of the world I guess, but kind of lame I can't use the classic mode.

Here is a link with sound: [imgur.com]

Thanks.

That is the beeper on the lcd

the skr mini has a serial port on it lcd connector

PA9 and PA10 are serial port 1

When used as a CR10_STOCKDISPLAY

You must make sure you don't have serial port 1 enabled anywhere
check these defines, none should be set to 1

SERIAL_PORT
SERIAL_PORT_2
SERIAL_PORT_3
LCD_SERIAL_PORT

The config I pulled out of the MarlinFirmware Configurations has SERIAL_PORT 2 and SERIAL_PORT_2 -1.

SERIAL_PORT_3 is set to 1, but commented out.

I don't see an LCD_SERIAL_PORT in the configuration.h.