Why would you have issues? The fact that you do not have a USA visa stamp in your passport is irrelevant to UK officials. You’re heading to India, not USA.
What is relevant is you have entry clearance for UK and are continuing to India, a country where you have an inalienable right to enter as a citizen.
Now if you’re illegally in the USA then they may have a cause for pause to refuse you entry despite your entry clearance because people who break immigration laws in one country are perceived to be more likely to break immigration and indeed other laws in other foreign countries.