H1b extension approved twice with different dates for same petition

[Greencardhelp]

I have applied for my H1b extension on December 28, 2018 and got approval on January 9th, 2019 with 3 years of approval(valid until Dec 2021). But after 3 months I have received another approval for same petition with same receipt number and this time my approval date was Dec 2019. what should I do now? Should I check with USCIS about my previous petition? I have two approved petitions and I want to keep the first one... what should I do now... please help