In contrast to Version 3.6.1,
in Version 3.7.0 on both Linux and Windows, when I encrypt a YAML file that accidentally has a duplicated key,
I cannot decrypt it afterwards.

Reproduce with sops test.yaml , duplicate the first line, and save.
Then try to decrypt, and get:

Error unmarshalling input yaml: yaml: unmarshal errors:
  line 2: mapping key "hello" already defined at line 1

The only way I found to recover the file would be to delete the offending key from the encrypted file
hello: ENC[AES256_GCM,data:nvp56OqVzo33WWLSyJubbsx4peUHNd/VQ3N4KXq2DRs4o5pf/3V3Hj8vg7DQUg==,iv:23E6rL8i155Ne1/SeGvsuc5OHku09sK9mhJv44Ky0gI=,tag:T0Dv5t+h3FMDYP7d2x01uw==,type:str]
and decrypt with sops --ignore-mac test.yaml