Masts can leak at the plug at the top. Water cal pool on top of the plug. The lower section heats and cools which can suck in moisture. Take the CompTip out and poke a hole through the foam plug to drain. You could then use a little air pressure into that hole to test for any other leak areas... using a soapy water test.
https://www.hobie.com/forums/viewtopic.php?f=18&t=169Re-seal with Sikaflex or 3M 5200.
Check the hull bottoms for wear. Water might be getting in under the seat pads. Peel off and re-seal using the Sikaflex or 5200.
You could drill a hole in an end cap of the rear beam and drain... check for other leaks as you did the mast section and hulls using the air and soapy water test.