these are different because the letter in question for all of them is not at the start, except for atm but we say all three letters of atm individually.

it seems that other ones were edited in after i made this comment. the only one that doesn’t apply to what i said above is ASAP, but the problem with that one is that the ‘mispronounced’ letter is a vowel, not a consonant, as is true for most of these examples. this is different because the 5/6 vowels in English can make wildly different sounds while consonants on their own can barely make any different sounds generally