There are two English dictionaries licensed by Google, the New Oxford American Dictionary (NOAD) and the Oxford Dictionary of English (ODE). While there is substantial overlap in their definitions (so substantial they are usually identical, as in your example), they are not the same dictionary. NOAD is an American English dictionary and therefore gives pronunciations for that dialect. Like most American dictionaries, it does not use IPA. ODE is British and has IPA and British pronunciations. These pronunciations are usually different!
Depending where you're located in the world, Google will give you one dictionary or the other.
Switching to ODE
While Google Dictionary does not have IPA for American English, you can check out ODE's British IPA by using the query parameter
gl=us would switch it back to NOAD. (These do not appear in the URL by default so you can just add them to the end.) For example, https://www.google.com/search?q=define+special&gl=gb.
To ease this, I created two bookmarklets to switch between English dictionaries in Google, which I originally published on ELU Meta.
Switch to British English:
Switch to American English:
It's probably best to just use another dictionary to get American IPA; they do exist. For example, there's Collins, which has definitions and IPA pronunciations from several reputable American dictionaries.
I personally tend to get my American IPA from one of the bilingual Oxford dictionaries licensed by Apple (available on Mac or iOS/iPadOS). They also have NOAD/ODE and their corresponding thesauri. Overall, it's a quicker way to access a dictionary or thesaurus.