Sounds like a reasonable theory but do you have an actual example? The one you gave:

> For example, a typical bilingual speaker of Indian English and Hindi will replace instances of the /æ/ phoneme (as in "blast" or "fast") with another phoneme like /a:/ (as in "father"). Which isn't that unusual since /æ/ is pretty uncommon among languages.

does not apply to Indian languages because most of them have daily-use-words with the /æ/ sound.