How can I fix the vi editor in Cygwin?

recently I was trying to run a c program using cygwin. The program called for a function fopen_s(). After compiling, I kept getting errors that this function did not exist. I did a bunch of trouble shooting but ultimately decided to just update cygwin since my version was kind of old. I did all of that and opened vi. while in vi the insert command wont work. I keep hitting 'i' but it just types 'i' to the screen. Backspace does not remove it, typing extra characters just creates undefined behavior. I can ':q!' to close vi, but so far I can't write a program.

Any ideas?

I just installed cygwin gcc-8.3.0, following the build instructions from https://preshing.com/20141108/how-to-install-the-latest-gcc-on-windows/

Thanks