Can decrypt without specifying key in command line but cannot re-encrypt

I am using age with sops.

age v1.1.1 & sops 3.7.3 on RHEL 7.9

I have my keys stored here: ~/.config/sops/age/keys.txt

I can execute sops <encrypted_file> and it will open up the decrypted version of the file in vim. Great.
I can execute sops -d -i <encrypted_file> and it will decrypt the file.

But when I run sops -e -i <unencrypted_file> i get the error “config file not found and no keys provided through command line options”

so then if I do specify the key in the command line using -a agedjfjsk... it will encrypt them again and the decryption again works fine. I'm confused because if the decryption works without specifying a key and its able to find the correct key saved via configuration then why won't the encryption work?

I at one time may have naively ran sops --config thinking it would provide to me config information but it was to set a config location and I didn't pass a file in. Perhaps that did something to alter the encryption configuration. If so, how do i reset it back? Thanks.

Start with the reported sops commands and the key file at ~/.config/sops/age/keys.txt, reproducing decryption and re-encryption on the stated versions. Trace how configuration and key discovery differ between those entry points, then document or fix the behavior so the expected re-encryption outcome is clear.