When I click on claim reward, the address popping up is different from my main address, is it normal?

you can claim in v2 of the app which is now live on the play store, App Store coming shortly. Please read this medium article fully which explains everything https://legionnetwork.medium.com/legion-super-app-v2-launches-be4bea482a27

You can claim with your new wallet or previous wallet. Go to claim reward, and register this new wallet as the wallet that will earn all past and future rewards.