[maket]

As far as I'm aware, the rule is if the first syllable starts with a vowel, phonetically.

In your example "MVP", the first syllable starts with an "em", so a vowel. In "Minimal Viable Product" the first syllable starts with the consonant sound.

I had a major pain with this rule when dealing with auto-generation of some API documentation. It ended up just being an issue of detecting/guessing if the text was an abbreviation or some weird CamelCase thing.

[saganus]

Yeah, that's the way I've always done it because otherwise it sounds wrong. I guess someone taught me the rule and I don't remember or something.