If you didn’t then your code doesn’t produce the exact same output. You wrote:
but the base64 value would suggest you converted 7e26997b-09a9-4f6e-b406-7372e3a5c370, which differs in the second byte of the node value:
- 73 27 e3 a5 c3 70 (your GUID)
- 73 72 e3 a5 c3 70 (the encoded base64 value)
Everything suggests that 7e26997b-09a9-4f6e-b406-7327e3a5c370 would encode to e5kmfqkJbk+0BnMn46XDcA==:
e5kmfqkJbk+0BnNy46XDcA==e5kmfqkJbk+0BnMn46XDcA==